diff --git a/.vortex/installer/src/Command/DestinationAwareTrait.php b/.vortex/installer/src/Command/DestinationAwareTrait.php
index 99ff140a9..7061099e2 100644
--- a/.vortex/installer/src/Command/DestinationAwareTrait.php
+++ b/.vortex/installer/src/Command/DestinationAwareTrait.php
@@ -4,6 +4,7 @@
 
 namespace DrevOps\VortexInstaller\Command;
 
+use DrevOps\VortexInstaller\Utils\File;
 use Symfony\Component\Console\Input\InputInterface;
 use Symfony\Component\Console\Input\InputOption;
 
@@ -42,13 +43,13 @@ protected function getDestination(InputInterface $input): string {
       throw new \InvalidArgumentException('Destination must be a string.');
     }
 
-    if (!is_dir($destination)) {
+    if (!File::isDir($destination)) {
       throw new \InvalidArgumentException(
         sprintf('Destination directory does not exist: %s', $destination)
       );
     }
 
-    return realpath($destination) ?: $destination;
+    return File::realpath($destination);
   }
 
 }
diff --git a/.vortex/installer/src/Command/InstallCommand.php b/.vortex/installer/src/Command/InstallCommand.php
index 1ed72b447..afd765ea1 100644
--- a/.vortex/installer/src/Command/InstallCommand.php
+++ b/.vortex/installer/src/Command/InstallCommand.php
@@ -333,7 +333,7 @@ protected function handleValidate(InputInterface $input, OutputInterface $output
       return Command::FAILURE;
     }
 
-    $prompts_json = is_file($prompts_option) ? (string) file_get_contents($prompts_option) : $prompts_option;
+    $prompts_json = OptionsResolver::readJsonOption($prompts_option, '--prompts');
     $decoded = json_decode($prompts_json);
 
     if (!$decoded instanceof \stdClass) {
@@ -437,7 +437,7 @@ public function cleanup(): void {
     }
 
     $phar_path = \Phar::running(FALSE);
-    if (!empty($phar_path) && file_exists($phar_path)) {
+    if (!empty($phar_path) && File::exists($phar_path)) {
       File::remove($phar_path);
     }
   }
diff --git a/.vortex/installer/src/Downloader/Archiver.php b/.vortex/installer/src/Downloader/Archiver.php
index 1d18e3692..ea5667d22 100644
--- a/.vortex/installer/src/Downloader/Archiver.php
+++ b/.vortex/installer/src/Downloader/Archiver.php
@@ -53,11 +53,11 @@ public function detectFormat(string $archive_path): ?string {
    * {@inheritdoc}
    */
   public function validate(string $archive_path): void {
-    if (!file_exists($archive_path)) {
+    if (!File::exists($archive_path)) {
       throw new \RuntimeException(sprintf('Archive file does not exist: "%s".', $archive_path));
     }
 
-    if (filesize($archive_path) === 0) {
+    if (File::size($archive_path) === 0) {
       throw new \RuntimeException('Archive is empty.');
     }
 
@@ -125,7 +125,7 @@ protected function extractTar(string $archive_path, string $destination, bool $s
       throw new \RuntimeException(sprintf('Unable to extract tar archive to "%s": %s.', $destination, $e->getMessage()), $e->getCode(), $e);
     }
     finally {
-      if ($strip_first_level && is_dir($temp_dir)) {
+      if ($strip_first_level && File::isDir($temp_dir)) {
         File::remove($temp_dir);
       }
     }
@@ -167,7 +167,7 @@ protected function extractZip(string $archive_path, string $destination, bool $s
       throw new \RuntimeException(sprintf('Unable to extract ZIP archive to "%s": %s.', $destination, $e->getMessage()), $e->getCode(), $e);
     }
     finally {
-      if ($strip_first_level && is_dir($temp_dir)) {
+      if ($strip_first_level && File::isDir($temp_dir)) {
         File::remove($temp_dir);
       }
     }
diff --git a/.vortex/installer/src/Downloader/RepositoryDownloader.php b/.vortex/installer/src/Downloader/RepositoryDownloader.php
index 2a1e20333..8d8dcafc8 100644
--- a/.vortex/installer/src/Downloader/RepositoryDownloader.php
+++ b/.vortex/installer/src/Downloader/RepositoryDownloader.php
@@ -56,7 +56,7 @@ public function download(Artifact $artifact, ?string $destination = NULL, ?strin
       $version = $this->downloadFromLocal($artifact, $destination);
     }
 
-    if (!is_readable($destination . '/composer.json')) {
+    if (!File::isReadable($destination . '/composer.json')) {
       throw new \RuntimeException('The downloaded repository does not contain a composer.json file.');
     }
 
@@ -130,9 +130,15 @@ protected function downloadFromRemote(Artifact $artifact, ?string $destination,
     $url = sprintf(self::ARCHIVE_URL_TEMPLATE, $repo_url, $ref);
 
     $archive_path = $this->downloadArchive($url);
-    $this->archiver->validate($archive_path);
-    $this->archiver->extract($archive_path, $destination, TRUE);
-    File::remove($archive_path);
+
+    try {
+      $this->archiver->validate($archive_path);
+      $this->archiver->extract($archive_path, $destination, TRUE);
+    }
+    finally {
+      // The archive is created inside a temporary directory of its own.
+      File::remove(dirname($archive_path));
+    }
 
     return $version;
   }
@@ -159,9 +165,15 @@ protected function downloadFromLocal(Artifact $artifact, ?string $destination):
     }
 
     $archive_path = $this->archiveFromLocal($artifact->getRepo(), $ref);
-    $this->archiver->validate($archive_path);
-    $this->archiver->extract($archive_path, $destination, FALSE);
-    File::remove($archive_path);
+
+    try {
+      $this->archiver->validate($archive_path);
+      $this->archiver->extract($archive_path, $destination, FALSE);
+    }
+    finally {
+      // The archive is created inside a temporary directory of its own.
+      File::remove(dirname($archive_path));
+    }
 
     return $version;
   }
@@ -177,7 +189,6 @@ protected function discoverLatestReleaseRemote(string $repo_url, ?string $releas
     $release_url = sprintf('https://api.github.com/repos/%s/releases', $path);
 
     $headers = self::requestHeaders($release_url, ['Accept' => 'application/vnd.github.v3+json']);
-    $github_token = Env::get('GITHUB_TOKEN');
 
     try {
       $response = $this->httpClient->request('GET', $release_url, ['headers' => $headers]);
@@ -188,7 +199,7 @@ protected function discoverLatestReleaseRemote(string $repo_url, ?string $releas
     }
 
     if ($release_contents === '' || $release_contents === '0') {
-      $message = sprintf('Unable to download release information from "%s"%s.', $release_url, $github_token ? ' (GitHub token was used)' : '');
+      $message = sprintf('Unable to download release information from "%s"%s.', $release_url, isset($headers['Authorization']) ? ' (GitHub token was used)' : '');
       throw new \RuntimeException($message);
     }
 
@@ -219,18 +230,14 @@ protected function discoverLatestReleaseRemote(string $repo_url, ?string $releas
    *   If download fails.
    */
   protected function downloadArchive(string $url): string {
-    $temp_file = tempnam(sys_get_temp_dir(), 'vortex_archive_');
-    if ($temp_file === FALSE) {
-      throw new \RuntimeException('Unable to create temporary file for archive download.');
-    }
+    $temp_dir = File::tmpdir(prefix: 'vortex_archive_');
+    $temp_file = $temp_dir . DIRECTORY_SEPARATOR . 'archive.tar.gz';
 
     try {
       $this->fileDownloader->download($url, $temp_file, self::requestHeaders($url));
     }
     catch (\RuntimeException $e) {
-      if (file_exists($temp_file)) {
-        File::remove($temp_file);
-      }
+      File::remove($temp_dir);
       throw new \RuntimeException(sprintf('Unable to download archive from "%s": %s.', $url, $e->getMessage()), $e->getCode(), $e);
     }
 
@@ -256,19 +263,18 @@ protected function archiveFromLocal(string $repo, string $ref): string {
       $this->git = new Git($repo);
     }
 
-    $temp_file = sys_get_temp_dir() . '/vortex_local_archive_' . uniqid() . '.tar';
+    $temp_dir = File::tmpdir(prefix: 'vortex_local_archive_');
+    $temp_file = $temp_dir . DIRECTORY_SEPARATOR . 'archive.tar';
 
     try {
       $this->git->run('archive', '--format=tar', $ref, '-o', $temp_file);
 
-      if (!file_exists($temp_file) || filesize($temp_file) === 0) {
+      if (!File::exists($temp_file) || File::size($temp_file) === 0) {
         throw new \RuntimeException('Archive creation produced empty file.');
       }
     }
     catch (\Exception $e) {
-      if (file_exists($temp_file)) {
-        File::remove($temp_file);
-      }
+      File::remove($temp_dir);
       throw new \RuntimeException(sprintf('Unable to create archive from local repository "%s": %s.', $repo, $e->getMessage()), $e->getCode(), $e);
     }
 
@@ -342,11 +348,11 @@ protected function validateRemoteRefExists(string $repo_url, string $ref): void
    *   If the repository does not exist or is not a valid git repository.
    */
   protected function validateLocalRepositoryExists(string $repo): void {
-    if (!is_dir($repo)) {
+    if (!File::isDir($repo)) {
       throw new \RuntimeException(sprintf('Local repository path does not exist: "%s".', $repo));
     }
 
-    if (!is_dir($repo . '/.git')) {
+    if (!File::isDir($repo . '/.git')) {
       throw new \RuntimeException(sprintf('Path is not a git repository: "%s".', $repo));
     }
   }
@@ -363,7 +369,7 @@ protected function validateLocalRepositoryExists(string $repo): void {
    *   If the reference does not exist.
    */
   protected function validateLocalRefExists(string $repo, string $ref): void {
-    $repo_path = (string) realpath($repo);
+    $repo_path = File::realpath($repo);
 
     if (!$this->git instanceof Git || $this->git->getRepositoryPath() !== $repo_path) {
       $this->git = new Git($repo);
diff --git a/.vortex/installer/src/Logger/FileLogger.php b/.vortex/installer/src/Logger/FileLogger.php
index bf44a5ff9..5b2039952 100644
--- a/.vortex/installer/src/Logger/FileLogger.php
+++ b/.vortex/installer/src/Logger/FileLogger.php
@@ -50,7 +50,7 @@ public function open(string $command, array $args = []): bool {
     $this->path = $this->getDir() . '/' . self::LOG_DIR . '/' . $name . '-' . date('Y-m-d-His') . '.log';
 
     $log_dir = dirname($this->path);
-    if (!is_dir($log_dir)) {
+    if (!File::isDir($log_dir)) {
       File::mkdir($log_dir);
     }
 
diff --git a/.vortex/installer/src/Prompts/Handlers/AssignAuthorPr.php b/.vortex/installer/src/Prompts/Handlers/AssignAuthorPr.php
index 3f1e4be7e..4a0622efd 100644
--- a/.vortex/installer/src/Prompts/Handlers/AssignAuthorPr.php
+++ b/.vortex/installer/src/Prompts/Handlers/AssignAuthorPr.php
@@ -37,7 +37,7 @@ public function discover(): null|string|bool|array {
       return NULL;
     }
 
-    return file_exists($this->destinationDir . '/.github/workflows/assign-author.yml');
+    return File::exists($this->destinationDir . '/.github/workflows/assign-author.yml');
   }
 
   /**
diff --git a/.vortex/installer/src/Prompts/Handlers/CiProvider.php b/.vortex/installer/src/Prompts/Handlers/CiProvider.php
index fe3ed1204..15ead9f93 100644
--- a/.vortex/installer/src/Prompts/Handlers/CiProvider.php
+++ b/.vortex/installer/src/Prompts/Handlers/CiProvider.php
@@ -60,11 +60,11 @@ public function discover(): null|string|bool|array {
       return NULL;
     }
 
-    if (is_readable($this->destinationDir . '/.github/workflows/build-test-deploy.yml')) {
+    if (File::exists($this->destinationDir . '/.github/workflows/build-test-deploy.yml')) {
       return self::GITHUB_ACTIONS;
     }
 
-    if (is_readable($this->destinationDir . '/.circleci/config.yml')) {
+    if (File::exists($this->destinationDir . '/.circleci/config.yml')) {
       return self::CIRCLECI;
     }
 
diff --git a/.vortex/installer/src/Prompts/Handlers/CodeCoverageProvider.php b/.vortex/installer/src/Prompts/Handlers/CodeCoverageProvider.php
index d17b6bd11..41c515ff1 100644
--- a/.vortex/installer/src/Prompts/Handlers/CodeCoverageProvider.php
+++ b/.vortex/installer/src/Prompts/Handlers/CodeCoverageProvider.php
@@ -53,13 +53,13 @@ public function discover(): null|string|bool|array {
 
     $gha_files = glob($this->destinationDir . '/.github/workflows/*.{yml,yaml}', GLOB_BRACE) ?: [];
     foreach ($gha_files as $gha_file) {
-      if (is_readable($gha_file) && File::contains($gha_file, 'codecov/codecov-action')) {
+      if (File::contains($gha_file, 'codecov/codecov-action')) {
         return self::CODECOV;
       }
     }
 
     $circle = $this->destinationDir . '/.circleci/config.yml';
-    if (is_readable($circle) && File::contains($circle, 'codecov -Z -s')) {
+    if (File::contains($circle, 'codecov -Z -s')) {
       return self::CODECOV;
     }
 
diff --git a/.vortex/installer/src/Prompts/Handlers/CodeProvider.php b/.vortex/installer/src/Prompts/Handlers/CodeProvider.php
index e54df7729..88edd32ab 100644
--- a/.vortex/installer/src/Prompts/Handlers/CodeProvider.php
+++ b/.vortex/installer/src/Prompts/Handlers/CodeProvider.php
@@ -54,11 +54,11 @@ public function default(array $responses): null|string|bool|array {
    * {@inheritdoc}
    */
   public function discover(): null|string|bool|array {
-    if (file_exists($this->destinationDir . '/.github')) {
+    if (File::exists($this->destinationDir . '/.github')) {
       return self::GITHUB;
     }
 
-    return $this->isInstalled() && file_exists($this->destinationDir . '/.git') ? self::OTHER : NULL;
+    return $this->isInstalled() && File::exists($this->destinationDir . '/.git') ? self::OTHER : NULL;
   }
 
   /**
@@ -71,8 +71,8 @@ public function process(): void {
     if ($v === self::GITHUB) {
       File::remove($t . '/.github/PULL_REQUEST_TEMPLATE.md');
 
-      if (file_exists($t . '/.github/PULL_REQUEST_TEMPLATE.dist.md')) {
-        rename($t . '/.github/PULL_REQUEST_TEMPLATE.dist.md', $t . '/.github/PULL_REQUEST_TEMPLATE.md');
+      if (File::exists($t . '/.github/PULL_REQUEST_TEMPLATE.dist.md')) {
+        File::rename($t . '/.github/PULL_REQUEST_TEMPLATE.dist.md', $t . '/.github/PULL_REQUEST_TEMPLATE.md');
       }
     }
     else {
diff --git a/.vortex/installer/src/Prompts/Handlers/CustomModules.php b/.vortex/installer/src/Prompts/Handlers/CustomModules.php
index 11440ced3..542ad8cb3 100644
--- a/.vortex/installer/src/Prompts/Handlers/CustomModules.php
+++ b/.vortex/installer/src/Prompts/Handlers/CustomModules.php
@@ -92,15 +92,15 @@ public function discover(): null|string|bool|array {
 
     $module_dir = $this->destinationDir . '/' . $this->webroot . '/modules/custom';
 
-    if (is_dir($module_dir . '/' . $prefix . '_base')) {
+    if (File::isDir($module_dir . '/' . $prefix . '_base')) {
       $modules[] = self::BASE;
     }
 
-    if (is_dir($module_dir . '/' . $prefix . '_demo')) {
+    if (File::isDir($module_dir . '/' . $prefix . '_demo')) {
       $modules[] = self::DEMO;
     }
 
-    if (is_dir($module_dir . '/' . $prefix . '_search')) {
+    if (File::isDir($module_dir . '/' . $prefix . '_search')) {
       $modules[] = self::SEARCH;
     }
 
@@ -220,7 +220,7 @@ protected function discoverModulePrefix(): ?string {
   protected static function removeDemoBehatFeatures(string $dir): void {
     $features_dir = $dir . '/tests/behat/features';
 
-    if (!is_dir($features_dir)) {
+    if (!File::isDir($features_dir)) {
       return;
     }
 
diff --git a/.vortex/installer/src/Prompts/Handlers/DependencyUpdatesProvider.php b/.vortex/installer/src/Prompts/Handlers/DependencyUpdatesProvider.php
index b29b8ecbe..cc94eb3bb 100644
--- a/.vortex/installer/src/Prompts/Handlers/DependencyUpdatesProvider.php
+++ b/.vortex/installer/src/Prompts/Handlers/DependencyUpdatesProvider.php
@@ -54,11 +54,11 @@ public function discover(): null|string|bool|array {
       return NULL;
     }
 
-    if (!is_readable($this->destinationDir . '/renovate.json')) {
+    if (!File::exists($this->destinationDir . '/renovate.json')) {
       return self::NONE;
     }
 
-    if (file_exists($this->destinationDir . '/.github/workflows/update-dependencies.yml')) {
+    if (File::exists($this->destinationDir . '/.github/workflows/update-dependencies.yml')) {
       return self::RENOVATEBOT_CI;
     }
 
diff --git a/.vortex/installer/src/Prompts/Handlers/Dotenv.php b/.vortex/installer/src/Prompts/Handlers/Dotenv.php
index 4fad17b53..fe03bd31b 100644
--- a/.vortex/installer/src/Prompts/Handlers/Dotenv.php
+++ b/.vortex/installer/src/Prompts/Handlers/Dotenv.php
@@ -5,6 +5,7 @@
 namespace DrevOps\VortexInstaller\Prompts\Handlers;
 
 use DrevOps\VortexInstaller\Utils\Env;
+use DrevOps\VortexInstaller\Utils\File;
 
 class Dotenv extends AbstractHandler {
 
@@ -22,7 +23,7 @@ public function discover(): null|string|bool|array {
   public function process(): void {
     $t = $this->tmpDir;
 
-    if (is_readable($this->destinationDir . '/.env')) {
+    if (File::exists($this->destinationDir . '/.env')) {
       $variables = Env::parseDotenv($this->destinationDir . '/.env');
       foreach ($variables as $name => $value) {
         Env::writeValueDotenv($name, $value, $t . '/.env');
diff --git a/.vortex/installer/src/Prompts/Handlers/Gitleaks.php b/.vortex/installer/src/Prompts/Handlers/Gitleaks.php
index 483749eaf..ba9c0d8c4 100644
--- a/.vortex/installer/src/Prompts/Handlers/Gitleaks.php
+++ b/.vortex/installer/src/Prompts/Handlers/Gitleaks.php
@@ -44,7 +44,7 @@ public function discover(): null|string|bool|array {
       return NULL;
     }
 
-    return file_exists($this->destinationDir . '/.gitleaks.toml');
+    return File::exists($this->destinationDir . '/.gitleaks.toml');
   }
 
   /**
diff --git a/.vortex/installer/src/Prompts/Handlers/HostingProjectName.php b/.vortex/installer/src/Prompts/Handlers/HostingProjectName.php
index e5efc2b09..36d8e626a 100644
--- a/.vortex/installer/src/Prompts/Handlers/HostingProjectName.php
+++ b/.vortex/installer/src/Prompts/Handlers/HostingProjectName.php
@@ -81,10 +81,10 @@ public function discover(): null|string|bool|array {
     // instead of a hardcoded project name. Kept for backward compatibility
     // with older installations.
     $acquia_settings_file = $this->destinationDir . sprintf('/%s/sites/default/includes/providers/settings.acquia.php', $this->webroot);
-    if (file_exists($acquia_settings_file)) {
-      $content = file_get_contents($acquia_settings_file);
+    if (File::isReadable($acquia_settings_file)) {
+      $content = File::read($acquia_settings_file);
       // Require '/var/www/site-php/your_site/your_site-settings.inc';.
-      if ($content !== FALSE && preg_match('/require\s+[\'"]\/var\/www\/site-php\/([a-z0-9_]+)\/[a-z0-9_]+-settings\.inc[\'"]\s*;/', $content, $matches) && !empty($matches[1])) {
+      if (preg_match('/require\s+[\'"]\/var\/www\/site-php\/([a-z0-9_]+)\/[a-z0-9_]+-settings\.inc[\'"]\s*;/', $content, $matches) && !empty($matches[1])) {
         return $matches[1];
       }
     }
@@ -95,9 +95,9 @@ public function discover(): null|string|bool|array {
     }
 
     $lagoon_site_file = $this->destinationDir . '/drush/sites/lagoon.site.yml';
-    if (file_exists($lagoon_site_file)) {
-      $content = file_get_contents($lagoon_site_file);
-      if ($content !== FALSE && preg_match('/user:\s*([a-z0-9_]+)-/', $content, $matches) && (!empty($matches[1]) && $matches[1] !== 'your_site')) {
+    if (File::isReadable($lagoon_site_file)) {
+      $content = File::read($lagoon_site_file);
+      if (preg_match('/user:\s*([a-z0-9_]+)-/', $content, $matches) && (!empty($matches[1]) && $matches[1] !== 'your_site')) {
         return $matches[1];
       }
     }
diff --git a/.vortex/installer/src/Prompts/Handlers/HostingProvider.php b/.vortex/installer/src/Prompts/Handlers/HostingProvider.php
index 928258f2a..099c126d8 100644
--- a/.vortex/installer/src/Prompts/Handlers/HostingProvider.php
+++ b/.vortex/installer/src/Prompts/Handlers/HostingProvider.php
@@ -62,11 +62,11 @@ public function default(array $responses): null|string|bool|array {
    * {@inheritdoc}
    */
   public function discover(): null|string|bool|array {
-    if (is_readable($this->destinationDir . '/hooks') || Env::getFromDotenv('VORTEX_FETCH_DB_SOURCE', $this->destinationDir) === DatabaseFetchSource::ACQUIA) {
+    if (File::exists($this->destinationDir . '/hooks') || Env::getFromDotenv('VORTEX_FETCH_DB_SOURCE', $this->destinationDir) === DatabaseFetchSource::ACQUIA) {
       return self::ACQUIA;
     }
 
-    if (is_readable($this->destinationDir . '/.lagoon.yml')) {
+    if (File::exists($this->destinationDir . '/.lagoon.yml')) {
       return self::LAGOON;
     }
 
diff --git a/.vortex/installer/src/Prompts/Handlers/Internal.php b/.vortex/installer/src/Prompts/Handlers/Internal.php
index c95b5d266..15d99bf70 100644
--- a/.vortex/installer/src/Prompts/Handlers/Internal.php
+++ b/.vortex/installer/src/Prompts/Handlers/Internal.php
@@ -77,8 +77,8 @@ public function process(): void {
       return $content;
     });
 
-    if (file_exists($t . '/README.dist.md')) {
-      rename($t . '/README.dist.md', $t . '/README.md');
+    if (File::exists($t . '/README.dist.md')) {
+      File::rename($t . '/README.dist.md', $t . '/README.md');
     }
 
     // Remove Vortex internal files.
@@ -162,7 +162,7 @@ protected function processDemoMode(array $responses, string $dir): void {
         $is_demo = FALSE;
       }
       elseif ($responses[ProvisionType::id()] === ProvisionType::DATABASE) {
-        $db_file_exists = file_exists(Env::get('VORTEX_DB_DIR', './.data') . '/' . Env::get('VORTEX_DB_FILE', 'db.sql'));
+        $db_file_exists = File::exists(Env::get('VORTEX_DB_DIR', './.data') . '/' . Env::get('VORTEX_DB_FILE', 'db.sql'));
         $has_comment = File::contains($this->destinationDir . '/.env', 'Override project-specific values for demonstration purposes');
 
         // Demo mode applies only to the URL and container registry download
diff --git a/.vortex/installer/src/Prompts/Handlers/LabelMergeConflictsPr.php b/.vortex/installer/src/Prompts/Handlers/LabelMergeConflictsPr.php
index 8320f38bb..ea1f0c8cb 100644
--- a/.vortex/installer/src/Prompts/Handlers/LabelMergeConflictsPr.php
+++ b/.vortex/installer/src/Prompts/Handlers/LabelMergeConflictsPr.php
@@ -37,7 +37,7 @@ public function discover(): null|string|bool|array {
       return NULL;
     }
 
-    return file_exists($this->destinationDir . '/.github/workflows/label-merge-conflict.yml');
+    return File::exists($this->destinationDir . '/.github/workflows/label-merge-conflict.yml');
   }
 
   /**
diff --git a/.vortex/installer/src/Prompts/Handlers/Modules.php b/.vortex/installer/src/Prompts/Handlers/Modules.php
index 3cf545b4c..1b6ec7e85 100644
--- a/.vortex/installer/src/Prompts/Handlers/Modules.php
+++ b/.vortex/installer/src/Prompts/Handlers/Modules.php
@@ -185,7 +185,7 @@ public static function getAvailableModules(): array {
    *   Array of module machine names (without drupal/ prefix), or NULL on error.
    */
   protected function getModulesFromComposerFile(string $composer_file): ?array {
-    if (!file_exists($composer_file)) {
+    if (!File::isReadable($composer_file)) {
       return NULL;
     }
 
diff --git a/.vortex/installer/src/Prompts/Handlers/PreserveDocsProject.php b/.vortex/installer/src/Prompts/Handlers/PreserveDocsProject.php
index de83c391a..25f518a5e 100644
--- a/.vortex/installer/src/Prompts/Handlers/PreserveDocsProject.php
+++ b/.vortex/installer/src/Prompts/Handlers/PreserveDocsProject.php
@@ -37,7 +37,7 @@ public function discover(): null|string|bool|array {
       return NULL;
     }
 
-    return file_exists($this->destinationDir . '/docs/README.md');
+    return File::exists($this->destinationDir . '/docs/README.md');
   }
 
   /**
diff --git a/.vortex/installer/src/Prompts/Handlers/Theme.php b/.vortex/installer/src/Prompts/Handlers/Theme.php
index 106bee8ae..a091f087e 100644
--- a/.vortex/installer/src/Prompts/Handlers/Theme.php
+++ b/.vortex/installer/src/Prompts/Handlers/Theme.php
@@ -127,7 +127,7 @@ public function process(): void {
 
     if (in_array($v, [self::OLIVERO, self::CLARO, self::STARK])) {
       $file_tmpl = self::findThemeFile($t, $w);
-      if (!empty($file_tmpl) && is_readable($file_tmpl)) {
+      if (!empty($file_tmpl) && File::exists($file_tmpl)) {
         File::remove(dirname($file_tmpl));
         File::rmdirIfEmpty(dirname($file_tmpl));
 
@@ -149,7 +149,7 @@ public function process(): void {
 
     if ($this->isInstalled() && (empty($file_dst) || !self::isVortexTheme(dirname($file_dst)))) {
       $file_tmpl = self::findThemeFile($t, $w);
-      if (!empty($file_tmpl) && is_readable($file_tmpl)) {
+      if (!empty($file_tmpl) && File::exists($file_tmpl)) {
         File::remove(dirname($file_tmpl));
       }
     }
@@ -211,8 +211,8 @@ protected static function findThemeFile(string $dir, string $webroot, ?string $t
   }
 
   protected static function isVortexTheme(string $dir): bool {
-    $c1 = file_exists($dir . '/scss/_variables.scss');
-    $c2 = file_exists($dir . '/package.json');
+    $c1 = File::exists($dir . '/scss/_variables.scss');
+    $c2 = File::exists($dir . '/package.json');
     $c3 = File::contains($dir . '/package.json', 'build-dev');
 
     return $c1 && $c2 && $c3;
diff --git a/.vortex/installer/src/Prompts/Handlers/VisualRegression.php b/.vortex/installer/src/Prompts/Handlers/VisualRegression.php
index 5c14bfffd..bbf74ed8a 100644
--- a/.vortex/installer/src/Prompts/Handlers/VisualRegression.php
+++ b/.vortex/installer/src/Prompts/Handlers/VisualRegression.php
@@ -60,7 +60,7 @@ public function discover(): null|string|bool|array {
       return NULL;
     }
 
-    return file_exists($this->destinationDir . '/.github/workflows/test-vr.yml');
+    return File::exists($this->destinationDir . '/.github/workflows/test-vr.yml');
   }
 
   /**
diff --git a/.vortex/installer/src/Prompts/Handlers/Webroot.php b/.vortex/installer/src/Prompts/Handlers/Webroot.php
index 389e3b776..2007c721c 100644
--- a/.vortex/installer/src/Prompts/Handlers/Webroot.php
+++ b/.vortex/installer/src/Prompts/Handlers/Webroot.php
@@ -150,7 +150,7 @@ public function process(): void {
 
     File::replaceContentAsync(fn(string $content): string => preg_replace('/=' . preg_quote($webroot, '/') . '\b/', '=' . $v, $content) ?? $content);
 
-    rename($t . '/' . $webroot, $t . '/' . $v);
+    File::rename($t . '/' . $webroot, $t . '/' . $v);
   }
 
 }
diff --git a/.vortex/installer/src/Utils/Env.php b/.vortex/installer/src/Utils/Env.php
index 04ef345ae..2f6bdff56 100644
--- a/.vortex/installer/src/Utils/Env.php
+++ b/.vortex/installer/src/Utils/Env.php
@@ -33,7 +33,7 @@ public static function getFromDotenv(string $name, string $dir): ?string {
     }
 
     $file = $dir . '/.env';
-    if (!is_readable($file)) {
+    if (!File::isReadable($file)) {
       return NULL;
     }
 
@@ -82,16 +82,11 @@ public static function putFromDotenv(string $filename = '.env', bool $override_e
    *   Array of parsed values, key is the variable name.
    */
   public static function parseDotenv(string $filename = '.env'): array {
-    if (!is_file($filename) || !is_readable($filename)) {
+    if (!File::isReadable($filename)) {
       return [];
     }
 
-    $contents = file_get_contents($filename);
-    if ($contents === FALSE) {
-      // @codeCoverageIgnoreStart
-      return [];
-      // @codeCoverageIgnoreEnd
-    }
+    $contents = File::read($filename);
 
     // Replace all # not inside quotes.
     $contents = preg_replace('/#(?=(?:(?:[^"]*"){2})*[^"]*$)/', ';', $contents);
@@ -140,16 +135,11 @@ public static function parseDotenv(string $filename = '.env'): array {
    *   Array of parsed values after modification.
    */
   public static function writeValueDotenv(string $name, ?string $value = NULL, string $filename = '.env', bool $enabled = TRUE): array {
-    if (!is_readable($filename)) {
+    if (!File::isReadable($filename)) {
       throw new \RuntimeException(sprintf('File "%s" is not readable.', $filename));
     }
 
-    $contents = file_get_contents($filename);
-    if ($contents === FALSE) {
-      // @codeCoverageIgnoreStart
-      throw new \RuntimeException(sprintf('Unable to read file "%s".', $filename));
-      // @codeCoverageIgnoreEnd
-    }
+    $contents = File::read($filename);
 
     // Pattern to match the variable name and its value, including multiline
     // quoted values. Matches both normal and commented-out variables.
@@ -185,11 +175,7 @@ public static function writeValueDotenv(string $name, ?string $value = NULL, str
       }
     }
 
-    if (file_put_contents($filename, $contents) === FALSE) {
-      // @codeCoverageIgnoreStart
-      throw new \RuntimeException(sprintf('Unable to write to file "%s".', $filename));
-      // @codeCoverageIgnoreEnd
-    }
+    File::dump($filename, $contents);
 
     return self::parseDotenv($filename);
   }
diff --git a/.vortex/installer/src/Utils/File.php b/.vortex/installer/src/Utils/File.php
index 37dfd7d1b..ca84481c3 100644
--- a/.vortex/installer/src/Utils/File.php
+++ b/.vortex/installer/src/Utils/File.php
@@ -5,7 +5,9 @@
 namespace DrevOps\VortexInstaller\Utils;
 
 use AlexSkrypnyk\File\ContentFile\ContentFile;
+use AlexSkrypnyk\File\Exception\FileException;
 use AlexSkrypnyk\File\File as UpstreamFile;
+use Symfony\Component\Filesystem\Filesystem;
 
 class File extends UpstreamFile {
 
@@ -30,6 +32,75 @@ public static function isInternal(string $path): bool {
     return in_array($path, self::internalPaths());
   }
 
+  /**
+   * Check if path is a regular file with readable contents.
+   *
+   * Distinct from exists(), which is also TRUE for a directory: this answers
+   * whether the path can be passed to read().
+   */
+  public static function isReadable(string $path): bool {
+    return is_file($path) && is_readable($path);
+  }
+
+  /**
+   * Check if an existing path can be written to.
+   *
+   * A dump() replaces a file by renaming a temporary one over it, which
+   * succeeds on a read-only file whose directory is writable, so a caller that
+   * must respect the file's own permissions checks them here first.
+   */
+  public static function isWritable(string $path): bool {
+    return is_writable($path);
+  }
+
+  /**
+   * Check if path is a directory.
+   *
+   * Distinct from exists(), which is also TRUE for a file.
+   */
+  public static function isDir(string $path): bool {
+    return is_dir($path);
+  }
+
+  /**
+   * Get the size of a file in bytes.
+   *
+   * @throws \AlexSkrypnyk\File\Exception\FileException
+   *   When the size cannot be read.
+   */
+  public static function size(string $path): int {
+    $size = @filesize($path);
+
+    if ($size === FALSE) {
+      throw new FileException(sprintf('Unable to read the size of "%s".', $path));
+    }
+
+    return $size;
+  }
+
+  /**
+   * Move a file or directory.
+   *
+   * An existing target is replaced by default, as rename() does; pass FALSE to
+   * fail instead.
+   *
+   * @throws \Symfony\Component\Filesystem\Exception\IOException
+   *   When the move fails.
+   */
+  public static function rename(string $origin, string $target, bool $overwrite = TRUE): void {
+    (new Filesystem())->rename($origin, $target, $overwrite);
+  }
+
+  /**
+   * Change the mode of a file or directory.
+   *
+   * @throws \Symfony\Component\Filesystem\Exception\IOException
+   *   When the mode cannot be changed.
+   */
+  public static function chmod(string $path, int $mode, bool $recursive = FALSE): void {
+    (new Filesystem())->chmod($path, $mode, 0000, $recursive);
+  }
+
   /**
    * Get list of internal paths.
    */
diff --git a/.vortex/installer/src/Utils/FileManager.php b/.vortex/installer/src/Utils/FileManager.php
index 7fea04713..e881b6ae1 100644
--- a/.vortex/installer/src/Utils/FileManager.php
+++ b/.vortex/installer/src/Utils/FileManager.php
@@ -145,12 +145,12 @@ public function prepareDestination(): array {
     $messages = [];
 
     $destination = $this->config->getDestination();
-    if (!is_dir($destination)) {
+    if (!File::isDir($destination)) {
       $destination = File::mkdir($destination);
       $messages[] = sprintf('Created directory "%s".', $destination);
     }
 
-    if (!is_readable($destination . '/.git')) {
+    if (!File::exists($destination . '/.git')) {
       $messages[] = sprintf('Initializing a new Git repository in directory "%s".', $destination);
 
       // The destination arrives from a CLI option, the environment or a config
@@ -160,7 +160,7 @@ public function prepareDestination(): array {
       $command = sprintf('git -c advice.defaultBranchName=false --work-tree=%s --git-dir=%s init > /dev/null', escapeshellarg($destination), escapeshellarg($destination . '/.git'));
       passthru($command, $exit_code);
 
-      if ($exit_code !== 0 || !File::exists($destination . '/.git')) {
+      if ($exit_code !== 0) {
         throw new \RuntimeException(sprintf('Unable to initialize Git repository in directory "%s".', $destination));
       }
     }
@@ -199,7 +199,7 @@ public function copyFiles(): void {
     }
 
     foreach ($ignored_files as $ignored_file) {
-      if (is_readable($ignored_file)) {
+      if (File::exists($ignored_file)) {
         File::remove($ignored_file);
       }
     }
@@ -210,11 +210,11 @@ public function copyFiles(): void {
 
     $this->recordReplacedChanges($src);
 
-    if (is_dir($src) && !File::dirIsEmpty($src)) {
+    if (File::isDir($src) && !File::dirIsEmpty($src)) {
       File::copy($src, $destination);
     }
 
-    if (!file_exists($destination . '/.env.local') && file_exists($destination . '/.env.local.example')) {
+    if (!File::exists($destination . '/.env.local') && File::exists($destination . '/.env.local.example')) {
       File::copy($destination . '/.env.local.example', $destination . '/.env.local');
     }
 
@@ -255,7 +255,7 @@ protected function removeExcludedPaths(array $paths, array $expected): void {
 
       $target = $destination . '/' . $path;
 
-      if (!is_file($target)) {
+      if (!File::isReadable($target)) {
         continue;
       }
 
@@ -302,7 +302,7 @@ protected function recordReplacedChanges(string $src): void {
     foreach ($this->relativePaths($src) as $path) {
       $project = $destination . '/' . $path;
 
-      if (!is_file($project)) {
+      if (!File::isReadable($project)) {
         continue;
       }
 
@@ -319,7 +319,7 @@ protected function recordReplacedChanges(string $src): void {
       // diff the project's copy against.
       $previous = $this->previousDir . '/' . $path;
 
-      $registry->add($path, is_file($previous) ? File::read($previous) : NULL, File::read($project), File::read($next));
+      $registry->add($path, File::isReadable($previous) ? File::read($previous) : NULL, File::read($project), File::read($next));
     }
 
     $this->registryFile = $registry->write((string) $this->previousRef, (string) $this->config->get(Config::VERSION), date('Y-m-d H:i:s'));
@@ -360,7 +360,7 @@ protected function hashDirectory(string $directory): array {
     foreach ($this->relativePaths($directory) as $path) {
       $file = $directory . '/' . $path;
 
-      if (is_file($file)) {
+      if (File::isReadable($file)) {
         $hashes[$path] = (string) hash_file(self::HASH_ALGO, $file);
       }
     }
@@ -378,7 +378,7 @@ protected function hashDirectory(string $directory): array {
    *   Relative file paths.
    */
   protected function relativePaths(string $directory): array {
-    if (!is_dir($directory)) {
+    if (!File::isDir($directory)) {
       return [];
     }
 
@@ -411,7 +411,7 @@ public function removeObsoletePaths(): void {
 
     foreach ($obsolete as $relative) {
       $path = $destination . '/' . $relative;
-      if (file_exists($path)) {
+      if (File::exists($path)) {
         File::remove($path);
       }
     }
@@ -445,12 +445,12 @@ public function prepareDemo(Downloader $downloader): array|string {
     $data_dir = $this->config->getDestination() . '/' . Env::get('VORTEX_DB_DIR', './.data');
     $db_file = Env::get('VORTEX_DB_FILE', 'db.sql');
 
-    if (file_exists($data_dir . '/' . $db_file)) {
+    if (File::exists($data_dir . '/' . $db_file)) {
       return 'Database dump file already exists. Skipping demo database fetch.';
     }
 
     $messages = [];
-    if (!file_exists($data_dir)) {
+    if (!File::exists($data_dir)) {
       $data_dir = File::mkdir($data_dir);
       $messages[] = sprintf('Created data directory "%s".', $data_dir);
     }
diff --git a/.vortex/installer/src/Utils/Git.php b/.vortex/installer/src/Utils/Git.php
index 5c7732253..223233a00 100644
--- a/.vortex/installer/src/Utils/Git.php
+++ b/.vortex/installer/src/Utils/Git.php
@@ -90,7 +90,7 @@ public static function extractOwnerRepo(string $uri): ?string {
    * @todo Refactor to use GitPhp.
    */
   public static function getTrackedFiles(string $dir): array {
-    if (!is_dir($dir . '/.git')) {
+    if (!File::isDir($dir . '/.git')) {
       throw new \RuntimeException('The directory is not a Git repository.');
     }
 
diff --git a/.vortex/installer/src/Utils/JsonManipulator.php b/.vortex/installer/src/Utils/JsonManipulator.php
index 78bfab75f..caed53353 100644
--- a/.vortex/installer/src/Utils/JsonManipulator.php
+++ b/.vortex/installer/src/Utils/JsonManipulator.php
@@ -14,20 +14,11 @@ public function __construct(protected string $contents) {
   }
 
   public static function fromFile(string $composer_json): ?self {
-    if (!is_readable($composer_json) || !is_file($composer_json)) {
+    if (!File::isReadable($composer_json)) {
       return NULL;
     }
 
-    $contents = file_get_contents($composer_json);
-    if ($contents === FALSE) {
-      // @codeCoverageIgnoreStart
-      throw new \RuntimeException(sprintf(
-        'Unable to read composer.json from %s: %s',
-        $composer_json,
-        error_get_last()['message'] ?? 'unknown error'
-      ));
-      // @codeCoverageIgnoreEnd
-    }
+    $contents = File::read($composer_json);
 
     try {
       $instance = new self($contents);
@@ -62,9 +53,7 @@ public static function updateFile(string $file, callable $callback): void {
     $callback($instance);
 
     $contents = $instance->getContents();
-    if (file_put_contents($file, $contents) !== strlen($contents)) {
-      throw new \RuntimeException(sprintf('Unable to write a JSON file at "%s".', $file));
-    }
+    File::dump($file, $contents);
   }
 
   /**
diff --git a/.vortex/installer/src/Utils/NpmLock.php b/.vortex/installer/src/Utils/NpmLock.php
index 15bfd6ac8..7e29de64e 100644
--- a/.vortex/installer/src/Utils/NpmLock.php
+++ b/.vortex/installer/src/Utils/NpmLock.php
@@ -41,7 +41,7 @@ class NpmLock {
   public static function sync(string $manifest_file): void {
     $lock_file = dirname($manifest_file) . DIRECTORY_SEPARATOR . self::FILE;
 
-    if (!is_file($lock_file)) {
+    if (!File::isReadable($lock_file)) {
       return;
     }
 
@@ -160,13 +160,7 @@ protected static function resolve(\stdClass $packages, string $from, string $nam
    * Decode a JSON file into objects.
    */
   protected static function read(string $file): \stdClass {
-    $contents = file_get_contents($file);
-
-    if ($contents === FALSE) {
-      // @codeCoverageIgnoreStart
-      throw new \RuntimeException(sprintf('Unable to read a JSON file at "%s".', $file));
-      // @codeCoverageIgnoreEnd
-    }
+    $contents = File::read($file);
 
     try {
       $decoded = json_decode($contents, FALSE, 512, JSON_THROW_ON_ERROR);
@@ -201,9 +195,11 @@ protected static function write(string $file, \stdClass $data): void {
 
     $json .= "\n";
 
-    if (!is_writable($file) || file_put_contents($file, $json) !== strlen($json)) {
+    if (!File::isWritable($file)) {
       throw new \RuntimeException(sprintf('Unable to write a JSON file at "%s".', $file));
     }
+
+    File::dump($file, $json);
   }
 
 }
diff --git a/.vortex/installer/src/Utils/OptionsResolver.php b/.vortex/installer/src/Utils/OptionsResolver.php
index f82393c58..ae3e2d0c0 100644
--- a/.vortex/installer/src/Utils/OptionsResolver.php
+++ b/.vortex/installer/src/Utils/OptionsResolver.php
@@ -35,6 +35,32 @@ public static function checkRequirements(ExecutableFinder $finder): void {
     }
   }
 
+  /**
+   * Read a JSON option given either as a file path or as a literal value.
+   *
+   * @param string $value
+   *   The option value.
+   * @param string $option
+   *   The option name, for the error message.
+   *
+   * @return string
+   *   The JSON string.
+   *
+   * @throws \RuntimeException
+   *   When the value names an existing path whose contents cannot be read.
+   */
+  public static function readJsonOption(string $value, string $option): string {
+    if (!File::exists($value)) {
+      return $value;
+    }
+
+    if (!File::isReadable($value)) {
+      throw new \RuntimeException(sprintf('Unable to read %s file: "%s".', $option, $value));
+    }
+
+    return File::read($value);
+  }
+
   /**
    * Instantiate configuration from CLI options and environment variables.
    *
@@ -53,8 +79,7 @@ public static function checkRequirements(ExecutableFinder $finder): void {
   public static function resolve(array $options): array {
     $config_json = '{}';
     if (isset($options['config']) && is_scalar($options['config'])) {
-      $config_candidate = (string) $options['config'];
-      $config_json = is_file($config_candidate) ? (string) file_get_contents($config_candidate) : $config_candidate;
+      $config_json = self::readJsonOption((string) $options['config'], '--config');
     }
 
     $config = Config::fromString($config_json);
@@ -102,7 +127,7 @@ public static function resolve(array $options): array {
       throw new \RuntimeException(sprintf('Invalid repository URI: %s.', $e->getMessage()), $e->getCode(), $e);
     }
 
-    $config->set(Config::IS_VORTEX_PROJECT, File::contains($config->getDestination() . '/README.md', '/badge\/Vortex-/'));
+    $config->set(Config::IS_VORTEX_PROJECT, File::contains($config->getDestination() . '/README.md', Version::BADGE_REGEX));
 
     // Flag to proceed with installation. If FALSE, the installation only
     // prints the resolved values and does not proceed.
@@ -117,16 +142,7 @@ public static function resolve(array $options): array {
     $config->set(Config::IS_DEMO_DB_FETCH_SKIP, (bool) Env::get(Config::IS_DEMO_DB_FETCH_SKIP, FALSE));
 
     if (isset($options['prompts']) && is_scalar($options['prompts'])) {
-      $prompts_candidate = (string) $options['prompts'];
-      if (is_file($prompts_candidate)) {
-        if (!is_readable($prompts_candidate)) {
-          throw new \RuntimeException(sprintf('Unable to read --prompts file: "%s".', $prompts_candidate));
-        }
-        $prompts_json = (string) file_get_contents($prompts_candidate);
-      }
-      else {
-        $prompts_json = $prompts_candidate;
-      }
+      $prompts_json = self::readJsonOption((string) $options['prompts'], '--prompts');
       $prompts = json_decode($prompts_json, TRUE);
 
       if (!is_array($prompts)) {
diff --git a/.vortex/installer/src/Utils/Tui.php b/.vortex/installer/src/Utils/Tui.php
index afbfaf29d..76fc5adf4 100644
--- a/.vortex/installer/src/Utils/Tui.php
+++ b/.vortex/installer/src/Utils/Tui.php
@@ -156,7 +156,7 @@ public static function caretUp(): string {
 
   public static function caretEol(string $text): string {
     $lines = explode(PHP_EOL, $text);
-    $longest = max(array_map(strlen(...), $lines));
+    $longest = max(array_map(Strings::strlenPlain(...), $lines));
 
     return "\033[" . $longest . "C";
   }
diff --git a/.vortex/installer/src/Utils/UpdateRegistry.php b/.vortex/installer/src/Utils/UpdateRegistry.php
index 517b387b5..a3623c51f 100644
--- a/.vortex/installer/src/Utils/UpdateRegistry.php
+++ b/.vortex/installer/src/Utils/UpdateRegistry.php
@@ -98,7 +98,14 @@ public function write(string $from, string $to, string $time): ?string {
     }
 
     $file = $this->destination . '/' . self::FILE;
-    $existing = is_file($file) ? File::read($file) : self::HEADING . PHP_EOL;
+
+    // A registry that exists but cannot be read would otherwise be replaced by
+    // the heading, discarding every entry recorded before this run.
+    if (File::exists($file) && !File::isReadable($file)) {
+      throw new \RuntimeException(sprintf('Unable to read the update registry "%s".', $file));
+    }
+
+    $existing = File::exists($file) ? File::read($file) : self::HEADING . PHP_EOL;
 
     File::dump($file, $existing . $content);
 
diff --git a/.vortex/installer/src/Utils/Version.php b/.vortex/installer/src/Utils/Version.php
index 0e17bbfdf..e2916cf08 100644
--- a/.vortex/installer/src/Utils/Version.php
+++ b/.vortex/installer/src/Utils/Version.php
@@ -15,6 +15,14 @@
  */
 class Version {
 
+  /**
+   * Pattern matching the Vortex badge in a project README.
+   *
+   * The capture group holds the git reference the badge was stamped with, so
+   * a README that matches is one a reference can be read from.
+   */
+  const BADGE_REGEX = '#badge/Vortex-(.+?)-65ACBC\.svg#';
+
   /**
    * Extract the major version number from a version string.
    *
@@ -85,13 +93,13 @@ public static function majorFromConstraint(?string $constraint): ?int {
   public static function detectProjectRef(string $dir): ?string {
     $readme = $dir . '/README.md';
 
-    if (!is_file($readme)) {
+    if (!File::isReadable($readme)) {
       return NULL;
     }
 
-    $contents = (string) file_get_contents($readme);
+    $contents = File::read($readme);
 
-    if (!preg_match('#badge/Vortex-(.+?)-65ACBC\.svg#', $contents, $matches)) {
+    if (!preg_match(self::BADGE_REGEX, $contents, $matches)) {
       return NULL;
     }
 
@@ -117,11 +125,11 @@ public static function detectProjectRef(string $dir): ?string {
   public static function detectProjectMajor(string $dir): ?int {
     $composer_json = $dir . '/composer.json';
 
-    if (!is_file($composer_json)) {
+    if (!File::isReadable($composer_json)) {
       return NULL;
     }
 
-    $data = json_decode((string) file_get_contents($composer_json), TRUE);
+    $data = json_decode(File::read($composer_json), TRUE);
     if (!is_array($data)) {
       return NULL;
     }
diff --git a/.vortex/installer/src/Utils/Yaml.php b/.vortex/installer/src/Utils/Yaml.php
index 3d69acf12..ad3262209 100644
--- a/.vortex/installer/src/Utils/Yaml.php
+++ b/.vortex/installer/src/Utils/Yaml.php
@@ -10,7 +10,7 @@
 class Yaml extends SymfonyYaml {
 
   public static function validateFile(string $path): void {
-    if (!file_exists($path) || !is_readable($path)) {
+    if (!File::isReadable($path)) {
       throw new \RuntimeException(sprintf('File does not exist or is not readable: "%s".', $path));
     }
 
diff --git a/.vortex/installer/tests/Functional/Command/BuildCommandTest.php b/.vortex/installer/tests/Functional/Command/BuildCommandTest.php
index 739408af6..8e587a276 100644
--- a/.vortex/installer/tests/Functional/Command/BuildCommandTest.php
+++ b/.vortex/installer/tests/Functional/Command/BuildCommandTest.php
@@ -4,7 +4,7 @@
 
 namespace DrevOps\VortexInstaller\Tests\Functional\Command;
 
-use AlexSkrypnyk\File\File;
+use DrevOps\VortexInstaller\Utils\File;
 use DrevOps\VortexInstaller\Command\BuildCommand;
 use DrevOps\VortexInstaller\Command\CheckRequirementsCommand;
 use DrevOps\VortexInstaller\Logger\FileLoggerInterface;
diff --git a/.vortex/installer/tests/Functional/Command/CheckRequirementsCommandTest.php b/.vortex/installer/tests/Functional/Command/CheckRequirementsCommandTest.php
index 6685ffc62..3c4be9267 100644
--- a/.vortex/installer/tests/Functional/Command/CheckRequirementsCommandTest.php
+++ b/.vortex/installer/tests/Functional/Command/CheckRequirementsCommandTest.php
@@ -4,7 +4,7 @@
 
 namespace DrevOps\VortexInstaller\Tests\Functional\Command;
 
-use AlexSkrypnyk\File\File;
+use DrevOps\VortexInstaller\Utils\File;
 use DrevOps\VortexInstaller\Command\CheckRequirementsCommand;
 use DrevOps\VortexInstaller\Runner\ProcessRunner;
 use DrevOps\VortexInstaller\Runner\RunnerInterface;
diff --git a/.vortex/installer/tests/Functional/Command/InstallCommandTest.php b/.vortex/installer/tests/Functional/Command/InstallCommandTest.php
index 39b968f43..abbbc39c1 100644
--- a/.vortex/installer/tests/Functional/Command/InstallCommandTest.php
+++ b/.vortex/installer/tests/Functional/Command/InstallCommandTest.php
@@ -523,8 +523,8 @@ public function testInstallCommandMajorGate(?string $version, string $composer_j
     // Pre-populate the destination so it looks like an existing Vortex project:
     // the README badge flags it as a Vortex project and the composer.json
     // 'drevops/vortex-tooling' constraint carries the project's major.
-    $this->assertNotFalse(file_put_contents(self::$sut . '/README.md', '[![Vortex](https://img.shields.io/badge/Vortex-1.40.0-65ACBC.svg)](https://github.com/drevops/vortex)'));
-    $this->assertNotFalse(file_put_contents(self::$sut . '/composer.json', $composer_json));
+    File::dump(self::$sut . '/README.md', '[![Vortex](https://img.shields.io/badge/Vortex-1.40.0-65ACBC.svg)](https://github.com/drevops/vortex)');
+    File::dump(self::$sut . '/composer.json', $composer_json);
 
     static::applicationInitFromCommand($install_command);
 
diff --git a/.vortex/installer/tests/Functional/PharTest.php b/.vortex/installer/tests/Functional/PharTest.php
index 1264b5f50..2b0ce6a91 100644
--- a/.vortex/installer/tests/Functional/PharTest.php
+++ b/.vortex/installer/tests/Functional/PharTest.php
@@ -84,7 +84,7 @@ public function testPharOptionHelp(): void {
 
   protected static function buildPhar(string $destination): void {
     fwrite(STDERR, 'Building installer PHAR file...');
-    if (!file_exists('vendor')) {
+    if (!File::exists('vendor')) {
       $exit_code = 0;
       passthru('composer install --no-dev --optimize-autoloader >/dev/null 2>&1 ', $exit_code);
       if ($exit_code !== 0) {
diff --git a/.vortex/installer/tests/Functional/Prompts/Handlers/AbstractHandlerProcessTestCase.php b/.vortex/installer/tests/Functional/Prompts/Handlers/AbstractHandlerProcessTestCase.php
index ddc419153..059132549 100644
--- a/.vortex/installer/tests/Functional/Prompts/Handlers/AbstractHandlerProcessTestCase.php
+++ b/.vortex/installer/tests/Functional/Prompts/Handlers/AbstractHandlerProcessTestCase.php
@@ -89,7 +89,7 @@ public function testHandlerProcess(
   abstract public static function dataProviderHandlerProcess(): \Iterator;
 
   protected function assertCommon(): void {
-    if (file_exists(static::$root . '/scripts/vortex.yml')) {
+    if (File::exists(static::$root . '/scripts/vortex.yml')) {
       $this->assertFileEquals(static::$root . '/tests/behat/fixtures/image.jpg', static::$sut . '/tests/behat/fixtures/image.jpg', 'Binary files were not modified.');
     }
 
diff --git a/.vortex/installer/tests/Functional/Prompts/Handlers/ToolsHandlerProcessTest.php b/.vortex/installer/tests/Functional/Prompts/Handlers/ToolsHandlerProcessTest.php
index e9351cfb9..07ab299d6 100644
--- a/.vortex/installer/tests/Functional/Prompts/Handlers/ToolsHandlerProcessTest.php
+++ b/.vortex/installer/tests/Functional/Prompts/Handlers/ToolsHandlerProcessTest.php
@@ -7,6 +7,7 @@
 use DrevOps\VortexInstaller\Prompts\Handlers\CiProvider;
 use DrevOps\VortexInstaller\Prompts\Handlers\Theme;
 use DrevOps\VortexInstaller\Prompts\Handlers\Tools;
+use DrevOps\VortexInstaller\Utils\File;
 use PHPUnit\Framework\Attributes\CoversClass;
 
 #[CoversClass(Tools::class)]
@@ -718,7 +719,7 @@ protected static function assertNpmLockLacksPackages(string $manifest_file, arra
   protected static function readJson(string $file): array {
     self::assertFileExists($file);
 
-    return (array) json_decode((string) file_get_contents($file), TRUE, 512, JSON_THROW_ON_ERROR);
+    return (array) json_decode(File::read($file), TRUE, 512, JSON_THROW_ON_ERROR);
   }
 
 }
diff --git a/.vortex/installer/tests/Unit/Downloader/ArchiverTest.php b/.vortex/installer/tests/Unit/Downloader/ArchiverTest.php
index cdd0e5f50..e0969d030 100644
--- a/.vortex/installer/tests/Unit/Downloader/ArchiverTest.php
+++ b/.vortex/installer/tests/Unit/Downloader/ArchiverTest.php
@@ -4,7 +4,7 @@
 
 namespace DrevOps\VortexInstaller\Tests\Unit\Downloader;
 
-use AlexSkrypnyk\File\File;
+use DrevOps\VortexInstaller\Utils\File;
 use DrevOps\VortexInstaller\Downloader\Archiver;
 use DrevOps\VortexInstaller\Tests\Unit\UnitTestCase;
 use PHPUnit\Framework\Attributes\CoversClass;
@@ -124,7 +124,7 @@ public function testExtract(string $creator, bool $strip, string $expected_path)
     $this->archiver->extract($archive_path, $destination, $strip);
 
     $this->assertFileExists($destination . $expected_path);
-    $this->assertEquals('Test content', file_get_contents($destination . $expected_path));
+    $this->assertEquals('Test content', File::read($destination . $expected_path));
 
     if ($strip) {
       $this->assertFileDoesNotExist($destination . '/test_archive');
@@ -224,7 +224,7 @@ protected function createTestTarGz(): string {
     $phar->buildFromDirectory($temp_dir);
     $phar->compress(\Phar::GZ);
 
-    rename($temp_dir . '/test.tar.gz', $archive_path);
+    File::rename($temp_dir . '/test.tar.gz', $archive_path);
 
     return $archive_path;
   }
diff --git a/.vortex/installer/tests/Unit/Downloader/RepositoryDownloaderTest.php b/.vortex/installer/tests/Unit/Downloader/RepositoryDownloaderTest.php
index 9aae68f9e..28e4cbdcf 100644
--- a/.vortex/installer/tests/Unit/Downloader/RepositoryDownloaderTest.php
+++ b/.vortex/installer/tests/Unit/Downloader/RepositoryDownloaderTest.php
@@ -4,7 +4,7 @@
 
 namespace DrevOps\VortexInstaller\Tests\Unit\Downloader;
 
-use AlexSkrypnyk\File\File;
+use DrevOps\VortexInstaller\Utils\File;
 use DrevOps\VortexInstaller\Downloader\ArchiverInterface;
 use DrevOps\VortexInstaller\Downloader\Artifact;
 use DrevOps\VortexInstaller\Downloader\Downloader;
@@ -469,129 +469,168 @@ public function testDownloadArchiveWithGithubToken(): void {
     $this->assertEquals('develop', $version);
   }
 
-  public function testValidateRemoteRepositoryExistsWithNotFoundError(): void {
-    $mock_http_client = $this->createMock(ClientInterface::class);
-    $mock_response = $this->createMock(ResponseInterface::class);
-    $mock_response->method('getStatusCode')->willReturn(404);
-    $mock_http_client->method('request')->willReturn($mock_response);
-    $destination = self::$tmp . '/destination_' . uniqid();
-    File::mkdir($destination);
-    $downloader = new RepositoryDownloader($mock_http_client);
-    $this->expectException(\RuntimeException::class);
-    $this->expectExceptionMessage('Repository not found or not accessible: "https://github.com/user/nonexistent" (HTTP 404)');
-    $downloader->download(Artifact::create('https://github.com/user/nonexistent', '1.0.0'), $destination);
-  }
+  /**
+   * @param \Closure(self):array{0:?\GuzzleHttp\ClientInterface,1:string} $setup
+   *   Builds the HTTP client (NULL for a local repository) and the repository
+   *   to download from.
+   * @param string $ref
+   *   Reference to download.
+   * @param string $expected_message
+   *   Substring the thrown message must contain.
+   */
+  #[DataProvider('dataProviderValidateFailure')]
+  public function testValidateFailure(\Closure $setup, string $ref, string $expected_message): void {
+    [$http_client, $repo] = $setup($this);
 
-  public function testValidateRemoteRefExistsWithNotFoundError(): void {
-    $mock_http_client = $this->createMock(ClientInterface::class);
-    $repo_response = $this->createMock(ResponseInterface::class);
-    $repo_response->method('getStatusCode')->willReturn(200);
-    $ref_response = $this->createMock(ResponseInterface::class);
-    $ref_response->method('getStatusCode')->willReturn(404);
-    $mock_http_client->method('request')->willReturnCallback(function ($method, $url) use ($repo_response, $ref_response): ResponseInterface {
-      if (str_contains($url, '/archive/')) {
-        return $ref_response;
-      }
-      return $repo_response;
-    });
     $destination = self::$tmp . '/destination_' . uniqid();
     File::mkdir($destination);
-    $downloader = new RepositoryDownloader($mock_http_client);
-    $this->expectException(\RuntimeException::class);
-    $this->expectExceptionMessage('Reference "nonexistent-tag" not found in repository "https://github.com/user/repo"');
-    $downloader->download(Artifact::create('https://github.com/user/repo', 'nonexistent-tag'), $destination);
-  }
 
-  public function testValidateLocalRepositoryExistsWithNonexistentPath(): void {
-    $nonexistent_path = self::$tmp . '/nonexistent_repo_' . uniqid();
-    $destination = self::$tmp . '/destination_' . uniqid();
-    File::mkdir($destination);
-    $downloader = new RepositoryDownloader();
+    $downloader = new RepositoryDownloader($http_client);
+
     $this->expectException(\RuntimeException::class);
-    $this->expectExceptionMessage(sprintf('Local repository path does not exist: "%s"', $nonexistent_path));
-    $downloader->download(Artifact::create($nonexistent_path, 'main'), $destination);
+    $this->expectExceptionMessage($expected_message);
+
+    $downloader->download(Artifact::create($repo, $ref), $destination);
   }
 
-  public function testValidateLocalRepositoryExistsWithNonGitDirectory(): void {
-    $non_git_path = self::$tmp . '/non_git_dir_' . uniqid();
-    File::mkdir($non_git_path);
-    $destination = self::$tmp . '/destination_' . uniqid();
-    File::mkdir($destination);
-    $downloader = new RepositoryDownloader();
-    $this->expectException(\RuntimeException::class);
-    $this->expectExceptionMessage(sprintf('Path is not a git repository: "%s"', $non_git_path));
-    $downloader->download(Artifact::create($non_git_path, 'main'), $destination);
+  public static function dataProviderValidateFailure(): \Iterator {
+    yield 'remote repository not found' => [
+      static fn(self $test): array => [$test->stubStatusClient(404), 'https://github.com/user/nonexistent'],
+      '1.0.0',
+      'Repository not found or not accessible: "https://github.com/user/nonexistent" (HTTP 404)',
+    ];
+
+    yield 'remote ref not found' => [
+      static fn(self $test): array => [$test->stubRefClient(404), 'https://github.com/user/repo'],
+      'nonexistent-tag',
+      'Reference "nonexistent-tag" not found in repository "https://github.com/user/repo"',
+    ];
+
+    yield 'remote repository unreachable' => [
+      static fn(self $test): array => [$test->stubThrowingClient('Connection timeout'), 'https://github.com/user/repo'],
+      '1.0.0',
+      'Unable to access repository "https://github.com/user/repo": Connection timeout.',
+    ];
+
+    yield 'remote ref unverifiable' => [
+      static fn(self $test): array => [$test->stubRefClient(NULL, 'Network error'), 'https://github.com/user/repo'],
+      'test-tag',
+      'Unable to verify reference "test-tag" in repository "https://github.com/user/repo": Network error.',
+    ];
+
+    yield 'local path missing' => [
+      static function (self $test): array {
+        $path = self::$tmp . '/nonexistent_repo_' . uniqid();
+
+        return [NULL, $path];
+      },
+      'main',
+      'Local repository path does not exist: ',
+    ];
+
+    yield 'local path not a git repository' => [
+      static function (self $test): array {
+        $path = self::$tmp . '/non_git_dir_' . uniqid();
+        File::mkdir($path);
+
+        return [NULL, $path];
+      },
+      'main',
+      'Path is not a git repository: ',
+    ];
   }
 
-  public function testValidateRemoteRepositoryExistsWithRequestException(): void {
-    $mock_http_client = $this->createMock(ClientInterface::class);
-    $mock_http_client->method('request')->willThrowException(new RequestException('Connection timeout', $this->createMock(RequestInterface::class)));
-    $destination = self::$tmp . '/destination_' . uniqid();
-    File::mkdir($destination);
-    $downloader = new RepositoryDownloader($mock_http_client);
-    $this->expectException(\RuntimeException::class);
-    $this->expectExceptionMessage('Unable to access repository "https://github.com/user/repo": Connection timeout.');
-    $downloader->download(Artifact::create('https://github.com/user/repo', '1.0.0'), $destination);
+  /**
+   * Stub a client answering every request with a single status code.
+   */
+  protected function stubStatusClient(int $status_code): ClientInterface {
+    $client = $this->createMock(ClientInterface::class);
+    $response = $this->createMock(ResponseInterface::class);
+    $response->method('getStatusCode')->willReturn($status_code);
+    $client->method('request')->willReturn($response);
+
+    return $client;
   }
 
-  public function testValidateRemoteRefExistsWithRequestException(): void {
-    $mock_http_client = $this->createMock(ClientInterface::class);
+  /**
+   * Stub a client where the repository resolves and the archive request fails.
+   *
+   * @param int|null $status_code
+   *   Status code for the archive request, or NULL to throw instead.
+   * @param string|null $exception_message
+   *   Message for the thrown request exception when no status code is given.
+   */
+  protected function stubRefClient(?int $status_code, ?string $exception_message = NULL): ClientInterface {
+    $client = $this->createMock(ClientInterface::class);
     $repo_response = $this->createMock(ResponseInterface::class);
     $repo_response->method('getStatusCode')->willReturn(200);
-    $mock_http_client->method('request')->willReturnCallback(function ($method, $url) use ($repo_response): ResponseInterface {
-      if (str_contains($url, '/archive/')) {
-        throw new RequestException('Network error', $this->createMock(RequestInterface::class));
+
+    $ref_response = NULL;
+    if ($status_code !== NULL) {
+      $ref_response = $this->createMock(ResponseInterface::class);
+      $ref_response->method('getStatusCode')->willReturn($status_code);
+    }
+
+    $request = $this->createMock(RequestInterface::class);
+    $client->method('request')->willReturnCallback(function ($method, $url) use ($repo_response, $ref_response, $exception_message, $request): ResponseInterface {
+      if (!str_contains($url, '/archive/')) {
+        return $repo_response;
       }
-      return $repo_response;
+
+      if (!$ref_response instanceof ResponseInterface) {
+        throw new RequestException((string) $exception_message, $request);
+      }
+
+      return $ref_response;
     });
-    $destination = self::$tmp . '/destination_' . uniqid();
-    File::mkdir($destination);
-    $downloader = new RepositoryDownloader($mock_http_client);
-    $this->expectException(\RuntimeException::class);
-    $this->expectExceptionMessage('Unable to verify reference "test-tag" in repository "https://github.com/user/repo": Network error.');
-    $downloader->download(Artifact::create('https://github.com/user/repo', 'test-tag'), $destination);
+
+    return $client;
   }
 
-  public function testValidateRemoteArtifactWithStableRef(): void {
-    $mock_http_client = $this->createMock(ClientInterface::class);
-    $mock_response = $this->createMock(ResponseInterface::class);
-    $mock_response->method('getStatusCode')->willReturn(200);
-    $mock_http_client->method('request')->willReturn($mock_response);
-    $downloader = new RepositoryDownloader($mock_http_client);
-    $artifact = Artifact::create('https://github.com/user/repo', 'stable');
-    $downloader->validate($artifact);
-    $this->expectNotToPerformAssertions();
+  /**
+   * Stub a client that fails every request with a transport error.
+   */
+  protected function stubThrowingClient(string $message): ClientInterface {
+    $client = $this->createMock(ClientInterface::class);
+    $client->method('request')->willThrowException(new RequestException($message, $this->createMock(RequestInterface::class)));
+
+    return $client;
   }
 
-  public function testValidateRemoteArtifactWithCustomRef(): void {
+  #[DataProvider('dataProviderValidateRemoteArtifact')]
+  public function testValidateRemoteArtifact(string $ref): void {
     $mock_http_client = $this->createMock(ClientInterface::class);
     $mock_response = $this->createMock(ResponseInterface::class);
     $mock_response->method('getStatusCode')->willReturn(200);
     $mock_http_client->method('request')->willReturn($mock_response);
     $downloader = new RepositoryDownloader($mock_http_client);
-    $artifact = Artifact::create('https://github.com/user/repo', 'v1.0.0');
-    $downloader->validate($artifact);
+
+    $downloader->validate(Artifact::create('https://github.com/user/repo', $ref));
+
     $this->expectNotToPerformAssertions();
   }
 
-  public function testValidateLocalArtifactWithHeadRef(): void {
-    $temp_repo_dir = $this->createGitRepo();
-    $downloader = new RepositoryDownloader();
-    $artifact = Artifact::create($temp_repo_dir, 'HEAD');
-    $downloader->validate($artifact);
-    $this->expectNotToPerformAssertions();
-    $this->removeGitRepo($temp_repo_dir);
+  public static function dataProviderValidateRemoteArtifact(): \Iterator {
+    yield 'stable ref' => ['stable'];
+    yield 'custom ref' => ['v1.0.0'];
   }
 
-  public function testValidateLocalArtifactWithCustomRef(): void {
+  #[DataProvider('dataProviderValidateLocalArtifact')]
+  public function testValidateLocalArtifact(string $ref): void {
     $temp_repo_dir = $this->createGitRepo();
     $downloader = new RepositoryDownloader();
-    $artifact = Artifact::create($temp_repo_dir, 'main');
-    $downloader->validate($artifact);
+
+    $downloader->validate(Artifact::create($temp_repo_dir, $ref));
+
     $this->expectNotToPerformAssertions();
     $this->removeGitRepo($temp_repo_dir);
   }
 
+  public static function dataProviderValidateLocalArtifact(): \Iterator {
+    yield 'HEAD ref' => ['HEAD'];
+    yield 'custom ref' => ['main'];
+  }
+
   protected function createMockHttpClient(int $status_code = 200, string $body_content = 'mock content'): ClientInterface {
     $mock_client = $this->createMock(ClientInterface::class);
     $mock_response = $this->createMock(ResponseInterface::class);
@@ -620,6 +659,10 @@ protected function createGitRepo(bool $with_composer_json = TRUE): string {
     $runner->run('git add .', output: new NullOutput());
     $runner->run('git', args: ['commit', '-m', 'Initial commit'], output: new NullOutput());
 
+    // 'git init' names the first branch after the machine's
+    // 'init.defaultBranch', so the tests that resolve 'main' pin it here.
+    $runner->run('git', args: ['branch', '-M', 'main'], output: new NullOutput());
+
     if ($with_composer_json) {
       File::dump($temp_repo_dir . '/composer.json', '{}');
       $runner->run('git add composer.json', output: new NullOutput());
diff --git a/.vortex/installer/tests/Unit/Logger/FileLoggerTest.php b/.vortex/installer/tests/Unit/Logger/FileLoggerTest.php
index fe8466653..7948cd305 100644
--- a/.vortex/installer/tests/Unit/Logger/FileLoggerTest.php
+++ b/.vortex/installer/tests/Unit/Logger/FileLoggerTest.php
@@ -4,7 +4,7 @@
 
 namespace DrevOps\VortexInstaller\Tests\Unit\Logger;
 
-use AlexSkrypnyk\File\File;
+use DrevOps\VortexInstaller\Utils\File;
 use DrevOps\VortexInstaller\Logger\FileLogger;
 use DrevOps\VortexInstaller\Tests\Unit\UnitTestCase;
 use PHPUnit\Framework\Attributes\CoversClass;
@@ -178,7 +178,7 @@ public function testWrite(string $content, bool $is_open, int $expected_writes):
       $logger->close();
       $path = $logger->getPath();
 
-      $written_content = file_get_contents((string) $path);
+      $written_content = File::read((string) $path);
       $expected_content = str_repeat($content, $expected_writes);
       $this->assertEquals($expected_content, $written_content, 'Written content should match expected content');
 
@@ -238,7 +238,7 @@ public function testClose(): void {
     // empty.
     $logger->write('should not be written');
 
-    $content = file_get_contents($path);
+    $content = File::read($path);
     $this->assertEquals('', $content, 'No content should be written after close()');
 
     $logger->close();
diff --git a/.vortex/installer/tests/Unit/Prompts/Handlers/AbstractHandlerDiscoveryTestCase.php b/.vortex/installer/tests/Unit/Prompts/Handlers/AbstractHandlerDiscoveryTestCase.php
index 29503a0d4..93e0116ab 100644
--- a/.vortex/installer/tests/Unit/Prompts/Handlers/AbstractHandlerDiscoveryTestCase.php
+++ b/.vortex/installer/tests/Unit/Prompts/Handlers/AbstractHandlerDiscoveryTestCase.php
@@ -253,7 +253,7 @@ public static function defaultTuiAnswers(): array {
 
   protected function stubComposerJsonValue(string $name, mixed $value): string {
     $composer_json = static::$sut . DIRECTORY_SEPARATOR . 'composer.json';
-    file_put_contents($composer_json, json_encode([$name => $value], JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES));
+    File::dump($composer_json, (string) json_encode([$name => $value], JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES));
 
     return $composer_json;
   }
@@ -263,9 +263,8 @@ protected function stubComposerJsonDependencies(array $dependencies, bool $is_de
     $section = $is_dev ? 'require-dev' : 'require';
 
     $data = [];
-    if (file_exists($composer_json)) {
-      $contents = file_get_contents($composer_json);
-      $existing = $contents !== FALSE ? json_decode($contents, TRUE) : NULL;
+    if (File::exists($composer_json)) {
+      $existing = json_decode(File::read($composer_json), TRUE);
       if ($existing) {
         $data = $existing;
       }
@@ -275,7 +274,7 @@ protected function stubComposerJsonDependencies(array $dependencies, bool $is_de
 
     $data[$section] = array_merge($data[$section], $dependencies);
 
-    file_put_contents($composer_json, json_encode($data, JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES));
+    File::dump($composer_json, (string) json_encode($data, JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES));
 
     return $composer_json;
   }
@@ -283,7 +282,12 @@ protected function stubComposerJsonDependencies(array $dependencies, bool $is_de
   protected function stubDotenvValue(string $name, mixed $value, string $filename = '.env'): string {
     $dotenv = static::$sut . DIRECTORY_SEPARATOR . $filename;
 
-    file_put_contents($dotenv, sprintf('%s=%s', $name, $value) . PHP_EOL, FILE_APPEND);
+    // append() requires the file to exist, and each stub may be the first.
+    if (!File::exists($dotenv)) {
+      File::dump($dotenv);
+    }
+
+    File::append($dotenv, sprintf('%s=%s', $name, $value) . PHP_EOL);
 
     return $dotenv;
   }
@@ -292,7 +296,12 @@ protected function stubVortexProject(Config $config): void {
     // Add a README.md file with a Vortex badge.
     $readme = static::$sut . DIRECTORY_SEPARATOR . 'README.md';
     $repo_url = str_replace('.git', '', RepositoryDownloader::DEFAULT_REPO);
-    file_put_contents($readme, sprintf('[![Vortex](https://img.shields.io/badge/Vortex-1.2.3-65ACBC.svg)](%s/tree/1.2.3)', $repo_url) . PHP_EOL, FILE_APPEND);
+
+    if (!File::exists($readme)) {
+      File::dump($readme);
+    }
+
+    File::append($readme, sprintf('[![Vortex](https://img.shields.io/badge/Vortex-1.2.3-65ACBC.svg)](%s/tree/1.2.3)', $repo_url) . PHP_EOL);
 
     $config->set(Config::IS_VORTEX_PROJECT, TRUE);
   }
diff --git a/.vortex/installer/tests/Unit/Prompts/Handlers/ToolsHandlerDiscoveryTest.php b/.vortex/installer/tests/Unit/Prompts/Handlers/ToolsHandlerDiscoveryTest.php
index c7026d711..6a8cb7329 100644
--- a/.vortex/installer/tests/Unit/Prompts/Handlers/ToolsHandlerDiscoveryTest.php
+++ b/.vortex/installer/tests/Unit/Prompts/Handlers/ToolsHandlerDiscoveryTest.php
@@ -38,7 +38,7 @@ function (AbstractHandlerDiscoveryTestCase $test, Config $config): void {
           'vincentlanglet/twig-cs-fixer' => '*',
         ];
         $test->stubComposerJsonDependencies($dependencies, TRUE);
-        file_put_contents(static::$sut . '/package.json', json_encode(['devDependencies' => ['eslint' => '*', 'jest' => '*', 'stylelint' => '*']], JSON_PRETTY_PRINT));
+        File::dump(static::$sut . '/package.json', (string) json_encode(['devDependencies' => ['eslint' => '*', 'jest' => '*', 'stylelint' => '*']], JSON_PRETTY_PRINT));
         File::dump(static::$sut . '/.dclintrc');
         File::dump(static::$sut . '/.circleci/config.yml', 'docker run --rm -i hadolint/hadolint');
       },
@@ -182,7 +182,7 @@ function (AbstractHandlerDiscoveryTestCase $test, Config $config): void {
       [Tools::id() => [Tools::JEST]] + $expected_installed,
       function (AbstractHandlerDiscoveryTestCase $test, Config $config): void {
         $test->stubVortexProject($config);
-        file_put_contents(static::$sut . '/package.json', json_encode(['devDependencies' => ['jest' => '*']], JSON_PRETTY_PRINT));
+        File::dump(static::$sut . '/package.json', (string) json_encode(['devDependencies' => ['jest' => '*']], JSON_PRETTY_PRINT));
       },
     ];
     yield 'tools - discovery - jest, alt' => [
@@ -198,7 +198,7 @@ function (AbstractHandlerDiscoveryTestCase $test, Config $config): void {
       [Tools::id() => [Tools::ESLINT]] + $expected_installed,
       function (AbstractHandlerDiscoveryTestCase $test, Config $config): void {
         $test->stubVortexProject($config);
-        file_put_contents(static::$sut . '/package.json', json_encode(['devDependencies' => ['eslint' => '*']], JSON_PRETTY_PRINT));
+        File::dump(static::$sut . '/package.json', (string) json_encode(['devDependencies' => ['eslint' => '*']], JSON_PRETTY_PRINT));
       },
     ];
     yield 'tools - discovery - eslint, alt' => [
@@ -214,7 +214,7 @@ function (AbstractHandlerDiscoveryTestCase $test, Config $config): void {
       [Tools::id() => [Tools::STYLELINT]] + $expected_installed,
       function (AbstractHandlerDiscoveryTestCase $test, Config $config): void {
         $test->stubVortexProject($config);
-        file_put_contents(static::$sut . '/package.json', json_encode(['devDependencies' => ['stylelint' => '*']], JSON_PRETTY_PRINT));
+        File::dump(static::$sut . '/package.json', (string) json_encode(['devDependencies' => ['stylelint' => '*']], JSON_PRETTY_PRINT));
       },
     ];
     yield 'tools - discovery - stylelint, alt' => [
diff --git a/.vortex/installer/tests/Unit/Prompts/InstallerPresenterTest.php b/.vortex/installer/tests/Unit/Prompts/InstallerPresenterTest.php
index dfb8b285d..d0a0bc0d4 100644
--- a/.vortex/installer/tests/Unit/Prompts/InstallerPresenterTest.php
+++ b/.vortex/installer/tests/Unit/Prompts/InstallerPresenterTest.php
@@ -32,14 +32,14 @@ protected function setUp(): void {
   }
 
   public function testConstructor(): void {
-    $config = new Config('/tmp/root', '/tmp/dst', '/tmp/tmp');
+    $config = $this->createConfig();
     $presenter = new InstallerPresenter($config);
 
     $this->assertInstanceOf(InstallerPresenter::class, $presenter);
   }
 
   public function testSetPromptManager(): void {
-    $config = new Config('/tmp/root', '/tmp/dst', '/tmp/tmp');
+    $config = $this->createConfig();
     $presenter = new InstallerPresenter($config);
 
     $mock_pm = $this->createMock(PromptManager::class);
@@ -51,7 +51,7 @@ public function testSetPromptManager(): void {
 
   #[DataProvider('dataProviderHeaderWithStableArtifact')]
   public function testHeaderWithStableArtifact(bool $is_vortex_project, bool $no_interaction): void {
-    $config = new Config('/tmp/root', '/tmp/dst', '/tmp/tmp');
+    $config = $this->createConfig();
     $config->set(Config::IS_VORTEX_PROJECT, $is_vortex_project);
     $config->setNoInteraction($no_interaction);
     $presenter = new InstallerPresenter($config);
@@ -73,7 +73,7 @@ public static function dataProviderHeaderWithStableArtifact(): \Iterator {
   }
 
   public function testHeaderWithDevelopmentArtifact(): void {
-    $config = new Config('/tmp/root', '/tmp/dst', '/tmp/tmp');
+    $config = $this->createConfig();
     $presenter = new InstallerPresenter($config);
 
     $artifact = Artifact::fromUri(RepositoryDownloader::DEFAULT_REPO . '#' . RepositoryDownloader::REF_HEAD);
@@ -84,7 +84,7 @@ public function testHeaderWithDevelopmentArtifact(): void {
   }
 
   public function testHeaderWithCustomArtifact(): void {
-    $config = new Config('/tmp/root', '/tmp/dst', '/tmp/tmp');
+    $config = $this->createConfig();
     $presenter = new InstallerPresenter($config);
 
     $artifact = Artifact::fromUri('https://github.com/drevops/vortex.git#abc123');
@@ -96,7 +96,7 @@ public function testHeaderWithCustomArtifact(): void {
   }
 
   public function testHeaderVersionPlaceholderReplacement(): void {
-    $config = new Config('/tmp/root', '/tmp/dst', '/tmp/tmp');
+    $config = $this->createConfig();
     $presenter = new InstallerPresenter($config);
 
     $artifact = Artifact::fromUri(NULL);
@@ -108,7 +108,7 @@ public function testHeaderVersionPlaceholderReplacement(): void {
   }
 
   public function testHeaderInteractiveShowsControls(): void {
-    $config = new Config('/tmp/root', '/tmp/dst', '/tmp/tmp');
+    $config = $this->createConfig();
     $config->setNoInteraction(FALSE);
     $presenter = new InstallerPresenter($config);
 
@@ -121,7 +121,7 @@ public function testHeaderInteractiveShowsControls(): void {
   }
 
   public function testHeaderNonInteractiveHidesControls(): void {
-    $config = new Config('/tmp/root', '/tmp/dst', '/tmp/tmp');
+    $config = $this->createConfig();
     $config->setNoInteraction(TRUE);
     $presenter = new InstallerPresenter($config);
 
@@ -135,7 +135,7 @@ public function testHeaderNonInteractiveHidesControls(): void {
   }
 
   public function testHeaderExistingVortexProject(): void {
-    $config = new Config('/tmp/root', '/tmp/dst', '/tmp/tmp');
+    $config = $this->createConfig();
     $config->set(Config::IS_VORTEX_PROJECT, TRUE);
     $presenter = new InstallerPresenter($config);
 
@@ -147,7 +147,7 @@ public function testHeaderExistingVortexProject(): void {
   }
 
   public function testFooterNewProject(): void {
-    $config = new Config('/tmp/root', '/tmp/dst', '/tmp/tmp');
+    $config = $this->createConfig();
     $config->set(Config::IS_VORTEX_PROJECT, FALSE);
     $presenter = new InstallerPresenter($config);
 
@@ -160,7 +160,7 @@ public function testFooterNewProject(): void {
   }
 
   public function testFooterExistingProject(): void {
-    $config = new Config('/tmp/root', '/tmp/dst', '/tmp/tmp');
+    $config = $this->createConfig();
     $config->set(Config::IS_VORTEX_PROJECT, TRUE);
     $presenter = new InstallerPresenter($config);
 
@@ -173,7 +173,7 @@ public function testFooterExistingProject(): void {
   }
 
   public function testFooterBuildSucceeded(): void {
-    $config = new Config('/tmp/root', '/tmp/dst', '/tmp/tmp');
+    $config = $this->createConfig();
     $presenter = new InstallerPresenter($config);
 
     $mock_pm = $this->createMock(PromptManager::class);
@@ -191,7 +191,7 @@ public function testFooterBuildSucceeded(): void {
   }
 
   public function testFooterBuildSucceededWithHandlerOutput(): void {
-    $config = new Config('/tmp/root', '/tmp/dst', '/tmp/tmp');
+    $config = $this->createConfig();
     $presenter = new InstallerPresenter($config);
 
     $mock_pm = $this->createMock(PromptManager::class);
@@ -208,7 +208,7 @@ public function testFooterBuildSucceededWithHandlerOutput(): void {
 
   #[DataProvider('dataProviderFooterBuildSkipped')]
   public function testFooterBuildSkipped(string $starter, bool $expect_profile_command, bool $expect_export_db): void {
-    $config = new Config('/tmp/root', '/tmp/dst', '/tmp/tmp');
+    $config = $this->createConfig();
     $presenter = new InstallerPresenter($config);
 
     $mock_pm = $this->createMock(PromptManager::class);
@@ -258,7 +258,7 @@ public static function dataProviderFooterBuildSkipped(): \Iterator {
   }
 
   public function testFooterBuildSkippedDefaultsToDemo(): void {
-    $config = new Config('/tmp/root', '/tmp/dst', '/tmp/tmp');
+    $config = $this->createConfig();
     $presenter = new InstallerPresenter($config);
 
     $mock_pm = $this->createMock(PromptManager::class);
@@ -274,7 +274,7 @@ public function testFooterBuildSkippedDefaultsToDemo(): void {
   }
 
   public function testFooterBuildFailed(): void {
-    $config = new Config('/tmp/root', '/tmp/dst', '/tmp/tmp');
+    $config = $this->createConfig();
     $presenter = new InstallerPresenter($config);
 
     $mock_pm = $this->createMock(PromptManager::class);
@@ -295,7 +295,7 @@ public function testFooterBuildFailed(): void {
   }
 
   public function testFooterBuildFailedWithHandlerOutput(): void {
-    $config = new Config('/tmp/root', '/tmp/dst', '/tmp/tmp');
+    $config = $this->createConfig();
     $presenter = new InstallerPresenter($config);
 
     $mock_pm = $this->createMock(PromptManager::class);
@@ -321,4 +321,11 @@ public static function dataProviderBuildResultConstants(): \Iterator {
     yield 'failed' => [InstallerPresenter::BUILD_RESULT_FAILED, 'failed'];
   }
 
+  /**
+   * Create a config with paths the presenter never reads from disk.
+   */
+  protected function createConfig(): Config {
+    return new Config(static::$tmp . '/root', static::$tmp . '/dst', static::$tmp . '/tmp');
+  }
+
 }
diff --git a/.vortex/installer/tests/Unit/Runner/ProcessRunnerTest.php b/.vortex/installer/tests/Unit/Runner/ProcessRunnerTest.php
index 2bdd5f2c2..7bddde35e 100644
--- a/.vortex/installer/tests/Unit/Runner/ProcessRunnerTest.php
+++ b/.vortex/installer/tests/Unit/Runner/ProcessRunnerTest.php
@@ -4,7 +4,7 @@
 
 namespace DrevOps\VortexInstaller\Tests\Unit\Runner;
 
-use AlexSkrypnyk\File\File;
+use DrevOps\VortexInstaller\Utils\File;
 use DrevOps\VortexInstaller\Runner\ProcessRunner;
 use DrevOps\VortexInstaller\Tests\Unit\UnitTestCase;
 use DrevOps\VortexInstaller\Utils\Tui;
@@ -298,7 +298,7 @@ public function testResolveCommandWithRelativePath(): void {
 
     $script_path = $test_dir . '/test_script.sh';
     File::dump($script_path, "#!/bin/sh\necho 'test'\n");
-    chmod($script_path, 0755);
+    File::chmod($script_path, 0755);
 
     $runner->setCwd(self::$tmp);
 
diff --git a/.vortex/installer/tests/Unit/UnitTestCase.php b/.vortex/installer/tests/Unit/UnitTestCase.php
index 63128ca51..0ed2ef6a2 100644
--- a/.vortex/installer/tests/Unit/UnitTestCase.php
+++ b/.vortex/installer/tests/Unit/UnitTestCase.php
@@ -10,6 +10,7 @@
 use AlexSkrypnyk\PhpunitHelpers\Traits\SerializableClosureTrait;
 use AlexSkrypnyk\PhpunitHelpers\UnitTestCase as UpstreamUnitTestCase;
 use AlexSkrypnyk\Snapshot\Testing\SnapshotTrait;
+use DrevOps\VortexInstaller\Utils\File;
 use DrevOps\VortexInstaller\Utils\Yaml;
 
 /**
@@ -64,12 +65,7 @@ protected function assertYamlFileIsValid(string $filename): void {
   protected function assertJsonFileIsValid(string $filename): void {
     $this->assertFileExists($filename);
 
-    $content = file_get_contents($filename);
-    if ($content === FALSE) {
-      $this->fail(sprintf('Failed to read JSON file "%s".', $filename));
-    }
-
-    $this->assertJson($content, sprintf('JSON validation for file %s failed: %s', $filename, json_last_error_msg()));
+    $this->assertJson(File::read($filename), sprintf('JSON validation for file %s failed: %s', $filename, json_last_error_msg()));
   }
 
 }
diff --git a/.vortex/installer/tests/Unit/Utils/EnvTest.php b/.vortex/installer/tests/Unit/Utils/EnvTest.php
index eb17ffffe..b101f52b5 100644
--- a/.vortex/installer/tests/Unit/Utils/EnvTest.php
+++ b/.vortex/installer/tests/Unit/Utils/EnvTest.php
@@ -117,7 +117,7 @@ public static function dataProviderPutFromDotenv(): \Iterator {
   public function testWriteValueDotenv(): void {
     $fixture_dir = dirname(__DIR__) . '/Fixtures/env';
     $actual_file = static::$sut . '/.env';
-    copy($fixture_dir . '/_baseline/.env', $actual_file);
+    File::copy($fixture_dir . '/_baseline/.env', $actual_file);
 
     // Apply updates to every variable to transform it to the after state.
     Env::writeValueDotenv('SIMPLE_VAR', 'new_simple_value', $actual_file);
@@ -235,12 +235,12 @@ public function testParseDotenvFileNotReadable(): void {
 
   public function testParseDotenvFileReadFailure(): void {
     $filename = $this->createFixtureEnvFile('VAR=value');
-    chmod($filename, 0000);
+    File::chmod($filename, 0000);
 
     $result = Env::parseDotenv($filename);
     $this->assertEquals([], $result);
 
-    chmod($filename, 0644);
+    File::chmod($filename, 0644);
     File::remove($filename);
   }
 
@@ -284,7 +284,7 @@ public function testGetFromDotenvReturnsParsedValue(): void {
     $dir = dirname($filename);
 
     $dotenv_file = $dir . '/.env';
-    rename($filename, $dotenv_file);
+    File::rename($filename, $dotenv_file);
 
     static::envUnset('TEST_VAR');
 
@@ -303,7 +303,7 @@ public function testWriteValueDotenvFileNotReadable(): void {
 
   public function testWriteValueDotenvFileReadFailure(): void {
     $filename = $this->createFixtureEnvFile('VAR=value');
-    chmod($filename, 0000);
+    File::chmod($filename, 0000);
 
     $this->expectException(\RuntimeException::class);
     $this->expectExceptionMessage(sprintf('File "%s" is not readable.', $filename));
@@ -312,7 +312,7 @@ public function testWriteValueDotenvFileReadFailure(): void {
       Env::writeValueDotenv('TEST_VAR', 'value', $filename);
     }
     finally {
-      chmod($filename, 0644);
+      File::chmod($filename, 0644);
       File::remove($filename);
     }
   }
@@ -322,7 +322,7 @@ public function testWriteValueDotenvAddNewVariableToFileWithoutNewline(): void {
 
     Env::writeValueDotenv('NEW_VAR', 'new_value', $filename);
 
-    $content = file_get_contents($filename);
+    $content = File::read($filename);
     $expected = "EXISTING_VAR=value\nNEW_VAR=new_value\n";
     $this->assertEquals($expected, $content);
 
@@ -334,7 +334,7 @@ public function testWriteValueDotenvReplaceVariableToFileWithoutNewline(): void
 
     Env::writeValueDotenv('NEW_VAR', 'new value with spaces', $filename);
 
-    $content = file_get_contents($filename);
+    $content = File::read($filename);
     $expected = "EXISTING_VAR=old_value\nNEW_VAR=\"new value with spaces\"\n";
     $this->assertEquals($expected, $content);
 
@@ -346,7 +346,7 @@ public function testWriteValueDotenvAddEmptyVariable(): void {
 
     Env::writeValueDotenv('NEW_VAR', NULL, $filename);
 
-    $content = file_get_contents($filename);
+    $content = File::read($filename);
     $expected = "EXISTING_VAR=value\nNEW_VAR=\n";
     $this->assertEquals($expected, $content);
 
@@ -358,7 +358,7 @@ public function testWriteValueDotenvAddEmptyVariableToFileWithoutNewline(): void
 
     Env::writeValueDotenv('NEW_VAR', NULL, $filename);
 
-    $content = file_get_contents($filename);
+    $content = File::read($filename);
     $expected = "EXISTING_VAR=value\nNEW_VAR=\n";
     $this->assertEquals($expected, $content);
 
@@ -371,7 +371,7 @@ public function testWriteValueDotenvWithEnabled(string $initial_content, string
 
     Env::writeValueDotenv($name, $value, $filename, $enabled);
 
-    $content = file_get_contents($filename);
+    $content = File::read($filename);
     $this->assertEquals($expected_content, $content);
 
     File::remove($filename);
@@ -472,10 +472,9 @@ public static function dataProviderWriteValueDotenvWithEnabled(): \Iterator {
   }
 
   public function testParseDotenvFileGetContentsFailure(): void {
-    // A directory in place of the file makes file_get_contents() fail.
-    $dirname = tempnam(sys_get_temp_dir(), '.env');
-    File::remove($dirname);
-    mkdir($dirname);
+    // A directory in place of the file is not readable as one.
+    $dirname = static::$tmp . '/' . uniqid('.env');
+    File::mkdir($dirname);
 
     $result = Env::parseDotenv($dirname);
     $this->assertEquals([], $result);
@@ -484,15 +483,9 @@ public function testParseDotenvFileGetContentsFailure(): void {
   }
 
   protected function createFixtureEnvFile(string $content): string {
-    $filename = tempnam(sys_get_temp_dir(), '.env');
-
-    if ($filename === FALSE) {
-      throw new \RuntimeException('Failed to create temporary file.');
-    }
+    $filename = static::$tmp . '/' . uniqid('.env');
 
-    if (file_put_contents($filename, $content) === FALSE) {
-      throw new \RuntimeException('Failed to write to temporary file.');
-    }
+    File::dump($filename, $content);
 
     return $filename;
   }
diff --git a/.vortex/installer/tests/Unit/Utils/FileManagerTest.php b/.vortex/installer/tests/Unit/Utils/FileManagerTest.php
index 43faef823..baf6b832f 100644
--- a/.vortex/installer/tests/Unit/Utils/FileManagerTest.php
+++ b/.vortex/installer/tests/Unit/Utils/FileManagerTest.php
@@ -13,6 +13,7 @@
 use DrevOps\VortexInstaller\Utils\FileManager;
 use DrevOps\VortexInstaller\Utils\UpdateRegistry;
 use PHPUnit\Framework\Attributes\CoversClass;
+use PHPUnit\Framework\Attributes\DataProvider;
 
 #[CoversClass(FileManager::class)]
 class FileManagerTest extends UnitTestCase {
@@ -25,128 +26,120 @@ protected function setUp(): void {
     static::envUnsetPrefix('VORTEX_DB');
   }
 
-  public function testConstructor(): void {
-    $config = new Config('/tmp/root', self::$sut, '/tmp/tmp');
-    $fm = new FileManager($config);
-
-    $this->assertInstanceOf(FileManager::class, $fm);
+  /**
+   * Create a config for a destination, staging from a source when given.
+   */
+  protected function createConfig(string $destination, ?string $src = NULL): Config {
+    return new Config(static::$tmp . '/root', $destination, $src ?? static::$tmp . '/staged');
   }
 
-  public function testPrepareDestinationExistingDirWithGit(): void {
-    $destination = self::$sut;
-    mkdir($destination . '/.git', 0777, TRUE);
-
-    $config = new Config('/tmp/root', $destination, '/tmp/tmp');
+  public function testConstructor(): void {
+    $config = $this->createConfig(self::$sut);
     $fm = new FileManager($config);
 
-    $messages = $fm->prepareDestination();
-
-    $this->assertEmpty($messages);
+    $this->assertInstanceOf(FileManager::class, $fm);
   }
 
-  public function testPrepareDestinationExistingDirWithoutGit(): void {
-    $destination = self::$sut;
-
-    $config = new Config('/tmp/root', $destination, '/tmp/tmp');
-    $fm = new FileManager($config);
-
-    $messages = $fm->prepareDestination();
-
-    $this->assertNotEmpty($messages);
-    $this->assertDirectoryExists($destination . '/.git');
-    $this->assertStringContainsString('Initializing a new Git repository', $messages[0]);
-  }
+  /**
+   * @param string $subdir
+   *   Path appended to the test directory to form the destination.
+   * @param bool $with_git
+   *   Create a repository in the destination before preparing it.
+   * @param array<int, string> $expected_messages
+   *   Substrings every returned message set must contain.
+   */
+  #[DataProvider('dataProviderPrepareDestination')]
+  public function testPrepareDestination(string $subdir, bool $with_git, array $expected_messages): void {
+    $destination = self::$sut . $subdir;
 
-  public function testPrepareDestinationCreatesNewDir(): void {
-    $destination = self::$sut . '/new_subdir';
+    if ($with_git) {
+      File::mkdir($destination . '/.git');
+    }
 
-    $config = new Config('/tmp/root', $destination, '/tmp/tmp');
-    $fm = new FileManager($config);
+    $fm = new FileManager($this->createConfig($destination));
 
     $messages = $fm->prepareDestination();
 
     $this->assertDirectoryExists($destination);
     $this->assertDirectoryExists($destination . '/.git');
+    $this->assertCount(count($expected_messages), $messages);
 
-    $has_created_msg = FALSE;
-    $has_git_msg = FALSE;
-    foreach ($messages as $message) {
-      if (str_contains($message, 'Created directory')) {
-        $has_created_msg = TRUE;
-      }
-      if (str_contains($message, 'Initializing a new Git repository')) {
-        $has_git_msg = TRUE;
-      }
+    foreach ($expected_messages as $index => $expected_message) {
+      $this->assertStringContainsString($expected_message, $messages[$index]);
     }
-    $this->assertTrue($has_created_msg);
-    $this->assertTrue($has_git_msg);
+  }
+
+  public static function dataProviderPrepareDestination(): \Iterator {
+    yield 'existing directory with a repository' => ['', TRUE, []];
+    yield 'existing directory without a repository' => ['', FALSE, ['Initializing a new Git repository']];
+    yield 'directory created by the install' => ['/new_subdir', FALSE, ['Created directory', 'Initializing a new Git repository']];
   }
 
   public function testCopyFilesCopiesToDestination(): void {
     $src = self::$sut . '/src_copy';
     $destination = self::$sut . '/dst_copy';
-    mkdir($src, 0777, TRUE);
-    mkdir($destination, 0777, TRUE);
-    file_put_contents($src . '/test.txt', 'content');
+    File::mkdir($src);
+    File::mkdir($destination);
+    File::dump($src . '/test.txt', 'content');
 
-    $config = new Config('/tmp/root', $destination, $src);
+    $config = $this->createConfig($destination, $src);
     $fm = new FileManager($config);
 
     $fm->copyFiles();
 
     $this->assertFileExists($destination . '/test.txt');
-    $this->assertEquals('content', file_get_contents($destination . '/test.txt'));
+    $this->assertEquals('content', File::read($destination . '/test.txt'));
   }
 
   public function testCopyFilesCreatesEnvLocal(): void {
     $src = self::$sut . '/src_envlocal';
     $destination = self::$sut . '/dst_envlocal';
-    mkdir($src, 0777, TRUE);
-    mkdir($destination, 0777, TRUE);
-    file_put_contents($src . '/test.txt', 'content');
+    File::mkdir($src);
+    File::mkdir($destination);
+    File::dump($src . '/test.txt', 'content');
 
-    $config = new Config('/tmp/root', $destination, $src);
+    $config = $this->createConfig($destination, $src);
     $fm = new FileManager($config);
 
     $fm->copyFiles();
 
     // Create the .env.local.example after copy.
-    file_put_contents($destination . '/.env.local.example', 'EXAMPLE=1');
+    File::dump($destination . '/.env.local.example', 'EXAMPLE=1');
 
     // Re-run to trigger the .env.local creation.
     // Recreate src for the second run.
-    mkdir($src, 0777, TRUE);
-    file_put_contents($src . '/dummy.txt', 'dummy');
+    File::mkdir($src);
+    File::dump($src . '/dummy.txt', 'dummy');
     $fm->copyFiles();
 
     $this->assertFileExists($destination . '/.env.local');
-    $this->assertEquals('EXAMPLE=1', file_get_contents($destination . '/.env.local'));
+    $this->assertEquals('EXAMPLE=1', File::read($destination . '/.env.local'));
   }
 
   public function testCopyFilesSkipsEnvLocalIfExists(): void {
     $src = self::$sut . '/src_envexist';
     $destination = self::$sut . '/dst_envexist';
-    mkdir($src, 0777, TRUE);
-    mkdir($destination, 0777, TRUE);
-    file_put_contents($src . '/test.txt', 'content');
-    file_put_contents($destination . '/.env.local', 'EXISTING=1');
-    file_put_contents($destination . '/.env.local.example', 'EXAMPLE=1');
+    File::mkdir($src);
+    File::mkdir($destination);
+    File::dump($src . '/test.txt', 'content');
+    File::dump($destination . '/.env.local', 'EXISTING=1');
+    File::dump($destination . '/.env.local.example', 'EXAMPLE=1');
 
-    $config = new Config('/tmp/root', $destination, $src);
+    $config = $this->createConfig($destination, $src);
     $fm = new FileManager($config);
 
     $fm->copyFiles();
 
-    $this->assertEquals('EXISTING=1', file_get_contents($destination . '/.env.local'));
+    $this->assertEquals('EXISTING=1', File::read($destination . '/.env.local'));
   }
 
   public function testCopyFilesHandlesEmptySrc(): void {
     $src = self::$sut . '/src_empty';
     $destination = self::$sut . '/dst_empty';
-    mkdir($src, 0777, TRUE);
-    mkdir($destination, 0777, TRUE);
+    File::mkdir($src);
+    File::mkdir($destination);
 
-    $config = new Config('/tmp/root', $destination, $src);
+    $config = $this->createConfig($destination, $src);
     $fm = new FileManager($config);
 
     $fm->copyFiles();
@@ -157,17 +150,17 @@ public function testCopyFilesHandlesEmptySrc(): void {
   public function testCopyFilesRemovesUnmodifiedExcludedPaths(): void {
     $src = self::$sut . '/src_excluded';
     $destination = self::$sut . '/dst_excluded';
-    file_put_contents(File::mkdir($src) . '/composer.json', '{}');
-    file_put_contents($src . '/phpstan.neon', 'parameters: []');
-    file_put_contents(File::mkdir($src . '/.circleci') . '/config.yml', 'version: 2.1');
+    File::dump(File::mkdir($src) . '/composer.json', '{}');
+    File::dump($src . '/phpstan.neon', 'parameters: []');
+    File::dump(File::mkdir($src . '/.circleci') . '/config.yml', 'version: 2.1');
 
-    $config = new Config('/tmp/root', $destination, $src);
+    $config = $this->createConfig($destination, $src);
     $config->set(Config::IS_VORTEX_PROJECT, TRUE, TRUE);
     $fm = new FileManager($config);
 
     // A previous install wrote both, unmodified since.
-    file_put_contents(File::mkdir($destination) . '/phpstan.neon', 'parameters: []');
-    file_put_contents(File::mkdir($destination . '/.circleci') . '/config.yml', 'version: 2.1');
+    File::dump(File::mkdir($destination) . '/phpstan.neon', 'parameters: []');
+    File::dump(File::mkdir($destination . '/.circleci') . '/config.yml', 'version: 2.1');
     $this->stubPreviousTemplate($fm, $destination, [
       'phpstan.neon' => 'parameters: []',
       '.circleci/config.yml' => 'version: 2.1',
@@ -190,15 +183,15 @@ public function testCopyFilesRemovesUnmodifiedExcludedPaths(): void {
   public function testCopyFilesKeepsModifiedExcludedPaths(): void {
     $src = self::$sut . '/src_modified';
     $destination = self::$sut . '/dst_modified';
-    file_put_contents(File::mkdir($src) . '/composer.json', '{}');
-    file_put_contents($src . '/phpstan.neon', 'parameters: []');
+    File::dump(File::mkdir($src) . '/composer.json', '{}');
+    File::dump($src . '/phpstan.neon', 'parameters: []');
 
-    $config = new Config('/tmp/root', $destination, $src);
+    $config = $this->createConfig($destination, $src);
     $config->set(Config::IS_VORTEX_PROJECT, TRUE, TRUE);
     $fm = new FileManager($config);
 
     // The project edited the file after the previous install wrote it.
-    file_put_contents(File::mkdir($destination) . '/phpstan.neon', "parameters:\n  level: 8");
+    File::dump(File::mkdir($destination) . '/phpstan.neon', "parameters:\n  level: 8");
     $this->stubPreviousTemplate($fm, $destination, ['phpstan.neon' => 'parameters: []']);
 
     $fm->snapshotTemplate();
@@ -213,16 +206,16 @@ public function testCopyFilesKeepsModifiedExcludedPaths(): void {
   public function testCopyFilesKeepsExcludedPathsWithoutRecordedHash(): void {
     $src = self::$sut . '/src_unverifiable';
     $destination = self::$sut . '/dst_unverifiable';
-    file_put_contents(File::mkdir($src) . '/composer.json', '{}');
-    file_put_contents($src . '/phpstan.neon', 'parameters: []');
+    File::dump(File::mkdir($src) . '/composer.json', '{}');
+    File::dump($src . '/phpstan.neon', 'parameters: []');
 
-    $config = new Config('/tmp/root', $destination, $src);
+    $config = $this->createConfig($destination, $src);
     $config->set(Config::IS_VORTEX_PROJECT, TRUE, TRUE);
     $fm = new FileManager($config);
     $fm->snapshotTemplate();
 
     // No previous version, so ownership cannot be established.
-    file_put_contents(File::mkdir($destination) . '/phpstan.neon', 'parameters: []');
+    File::dump(File::mkdir($destination) . '/phpstan.neon', 'parameters: []');
     File::remove($src . '/phpstan.neon');
 
     $fm->copyFiles();
@@ -233,10 +226,10 @@ public function testCopyFilesKeepsExcludedPathsWithoutRecordedHash(): void {
   public function testCopyFilesWritesNoManifest(): void {
     $src = self::$sut . '/src_no_manifest';
     $destination = self::$sut . '/dst_no_manifest';
-    file_put_contents(File::mkdir($src) . '/composer.json', '{}');
-    file_put_contents(File::mkdir($src . '/scripts') . '/provision.sh', 'echo 1');
+    File::dump(File::mkdir($src) . '/composer.json', '{}');
+    File::dump(File::mkdir($src . '/scripts') . '/provision.sh', 'echo 1');
 
-    $config = new Config('/tmp/root', $destination, $src);
+    $config = $this->createConfig($destination, $src);
     $fm = new FileManager($config);
     $fm->snapshotTemplate();
 
@@ -248,15 +241,15 @@ public function testCopyFilesWritesNoManifest(): void {
   public function testCopyFilesRemovesExcludedPathsMatchedOnlyAfterRendering(): void {
     $src = self::$sut . '/src_rendered';
     $destination = self::$sut . '/dst_rendered';
-    file_put_contents(File::mkdir($src) . '/composer.json', '{}');
-    file_put_contents($src . '/rector.php', 'paths: your_site');
+    File::dump(File::mkdir($src) . '/composer.json', '{}');
+    File::dump($src . '/rector.php', 'paths: your_site');
 
-    $config = new Config('/tmp/root', $destination, $src);
+    $config = $this->createConfig($destination, $src);
     $config->set(Config::IS_VORTEX_PROJECT, TRUE, TRUE);
     $fm = new FileManager($config);
 
     // The project holds the rendered content, which the download never has.
-    file_put_contents(File::mkdir($destination) . '/rector.php', 'paths: star_wars');
+    File::dump(File::mkdir($destination) . '/rector.php', 'paths: star_wars');
     $this->stubPreviousTemplate($fm, $destination, ['rector.php' => 'paths: your_site'], function (string $dir): void {
       File::dump($dir . '/rector.php', 'paths: star_wars');
     });
@@ -272,14 +265,14 @@ public function testCopyFilesRemovesExcludedPathsMatchedOnlyAfterRendering(): vo
   public function testCopyFilesRemovesExcludedPathsDeselectedByThisRun(): void {
     $src = self::$sut . '/src_deselected';
     $destination = self::$sut . '/dst_deselected';
-    file_put_contents(File::mkdir($src) . '/composer.json', '{}');
-    file_put_contents($src . '/jest.config.js', 'module.exports = {};');
+    File::dump(File::mkdir($src) . '/composer.json', '{}');
+    File::dump($src . '/jest.config.js', 'module.exports = {};');
 
-    $config = new Config('/tmp/root', $destination, $src);
+    $config = $this->createConfig($destination, $src);
     $config->set(Config::IS_VORTEX_PROJECT, TRUE, TRUE);
     $fm = new FileManager($config);
 
-    file_put_contents(File::mkdir($destination) . '/jest.config.js', 'module.exports = {};');
+    File::dump(File::mkdir($destination) . '/jest.config.js', 'module.exports = {};');
 
     // Discovery answers describe the project, which still has the tool, so
     // the render keeps the file even though this run deselects it.
@@ -296,15 +289,15 @@ public function testCopyFilesRemovesExcludedPathsDeselectedByThisRun(): void {
   public function testCopyFilesRecordsReplacedProjectChanges(): void {
     $src = self::$sut . '/src_registry';
     $destination = self::$sut . '/dst_registry';
-    file_put_contents(File::mkdir($src) . '/phpstan.neon', "parameters:\n  level: 9\n");
+    File::dump(File::mkdir($src) . '/phpstan.neon', "parameters:\n  level: 9\n");
 
-    $config = new Config('/tmp/root', $destination, $src);
+    $config = $this->createConfig($destination, $src);
     $config->set(Config::IS_VORTEX_PROJECT, TRUE, TRUE);
     $config->set(Config::VERSION, '1.41.0', TRUE);
     $fm = new FileManager($config);
 
     // The project edited the file the previous version installed.
-    file_put_contents(File::mkdir($destination) . '/phpstan.neon', "parameters:\n  level: 8\n");
+    File::dump(File::mkdir($destination) . '/phpstan.neon', "parameters:\n  level: 8\n");
     $this->stubPreviousTemplate($fm, $destination, ['phpstan.neon' => "parameters:\n  level: 5\n"]);
 
     $fm->snapshotTemplate();
@@ -324,13 +317,13 @@ public function testCopyFilesRecordsReplacedProjectChanges(): void {
   public function testCopyFilesRecordsNothingWithoutProjectChanges(): void {
     $src = self::$sut . '/src_no_registry';
     $destination = self::$sut . '/dst_no_registry';
-    file_put_contents(File::mkdir($src) . '/phpstan.neon', "parameters:\n  level: 9\n");
+    File::dump(File::mkdir($src) . '/phpstan.neon', "parameters:\n  level: 9\n");
 
-    $config = new Config('/tmp/root', $destination, $src);
+    $config = $this->createConfig($destination, $src);
     $config->set(Config::IS_VORTEX_PROJECT, TRUE, TRUE);
     $fm = new FileManager($config);
 
-    file_put_contents(File::mkdir($destination) . '/phpstan.neon', "parameters:\n  level: 5\n");
+    File::dump(File::mkdir($destination) . '/phpstan.neon', "parameters:\n  level: 5\n");
     $this->stubPreviousTemplate($fm, $destination, ['phpstan.neon' => "parameters:\n  level: 5\n"]);
 
     $fm->snapshotTemplate();
@@ -343,13 +336,13 @@ public function testCopyFilesRecordsNothingWithoutProjectChanges(): void {
   public function testCopyFilesRemovesCommittedManifest(): void {
     $src = self::$sut . '/src_stale_manifest';
     $destination = self::$sut . '/dst_stale_manifest';
-    file_put_contents(File::mkdir($src) . '/composer.json', '{}');
+    File::dump(File::mkdir($src) . '/composer.json', '{}');
 
-    $config = new Config('/tmp/root', $destination, $src);
+    $config = $this->createConfig($destination, $src);
     $config->set(Config::IS_VORTEX_PROJECT, TRUE, TRUE);
     $fm = new FileManager($config);
 
-    file_put_contents(File::mkdir($destination) . '/.vortex-manifest.json', '{"composer.json":"abc"}');
+    File::dump(File::mkdir($destination) . '/.vortex-manifest.json', '{"composer.json":"abc"}');
 
     $fm->copyFiles();
 
@@ -359,12 +352,12 @@ public function testCopyFilesRemovesCommittedManifest(): void {
   public function testCopyFilesKeepsManifestInDestinationThatIsNotVortexProject(): void {
     $src = self::$sut . '/src_foreign_manifest';
     $destination = self::$sut . '/dst_foreign_manifest';
-    file_put_contents(File::mkdir($src) . '/composer.json', '{}');
+    File::dump(File::mkdir($src) . '/composer.json', '{}');
 
-    $config = new Config('/tmp/root', $destination, $src);
+    $config = $this->createConfig($destination, $src);
     $fm = new FileManager($config);
 
-    file_put_contents(File::mkdir($destination) . '/.vortex-manifest.json', '{"owned":"by the project"}');
+    File::dump(File::mkdir($destination) . '/.vortex-manifest.json', '{"owned":"by the project"}');
 
     $fm->copyFiles();
 
@@ -374,15 +367,15 @@ public function testCopyFilesKeepsManifestInDestinationThatIsNotVortexProject():
   public function testCopyFilesKeepsPathsTheTemplateNeverShipped(): void {
     $src = self::$sut . '/src_unknown';
     $destination = self::$sut . '/dst_unknown';
-    file_put_contents(File::mkdir($src) . '/composer.json', '{}');
+    File::dump(File::mkdir($src) . '/composer.json', '{}');
 
-    $config = new Config('/tmp/root', $destination, $src);
+    $config = $this->createConfig($destination, $src);
     $config->set(Config::IS_VORTEX_PROJECT, TRUE, TRUE);
     $fm = new FileManager($config);
     $fm->snapshotTemplate();
 
-    file_put_contents(File::mkdir($destination) . '/phpstan.neon', 'project owned');
-    file_put_contents(File::mkdir($destination . '/web/modules/custom/mymodule') . '/mymodule.info.yml', 'name: My module');
+    File::dump(File::mkdir($destination) . '/phpstan.neon', 'project owned');
+    File::dump(File::mkdir($destination . '/web/modules/custom/mymodule') . '/mymodule.info.yml', 'name: My module');
 
     $fm->copyFiles();
 
@@ -393,14 +386,14 @@ public function testCopyFilesKeepsPathsTheTemplateNeverShipped(): void {
   public function testCopyFilesKeepsExcludedPathsForNonVortexProject(): void {
     $src = self::$sut . '/src_fresh';
     $destination = self::$sut . '/dst_fresh';
-    file_put_contents(File::mkdir($src) . '/composer.json', '{}');
-    file_put_contents($src . '/phpstan.neon', 'parameters: []');
+    File::dump(File::mkdir($src) . '/composer.json', '{}');
+    File::dump($src . '/phpstan.neon', 'parameters: []');
 
-    $config = new Config('/tmp/root', $destination, $src);
+    $config = $this->createConfig($destination, $src);
     $fm = new FileManager($config);
     $fm->snapshotTemplate();
 
-    file_put_contents(File::mkdir($destination) . '/phpstan.neon', 'project owned');
+    File::dump(File::mkdir($destination) . '/phpstan.neon', 'project owned');
     File::remove($src . '/phpstan.neon');
 
     $fm->copyFiles();
@@ -411,15 +404,15 @@ public function testCopyFilesKeepsExcludedPathsForNonVortexProject(): void {
   public function testCopyFilesKeepsHarnessPaths(): void {
     $src = self::$sut . '/src_harness';
     $destination = self::$sut . '/dst_harness';
-    file_put_contents(File::mkdir($src) . '/composer.json', '{}');
-    file_put_contents(File::mkdir($src . '/.vortex') . '/CLAUDE.md', 'harness');
+    File::dump(File::mkdir($src) . '/composer.json', '{}');
+    File::dump(File::mkdir($src . '/.vortex') . '/CLAUDE.md', 'harness');
 
-    $config = new Config('/tmp/root', $destination, $src);
+    $config = $this->createConfig($destination, $src);
     $config->set(Config::IS_VORTEX_PROJECT, TRUE, TRUE);
     $fm = new FileManager($config);
     $fm->snapshotTemplate();
 
-    file_put_contents(File::mkdir($destination . '/.vortex') . '/CLAUDE.md', 'project owned');
+    File::dump(File::mkdir($destination . '/.vortex') . '/CLAUDE.md', 'project owned');
     File::remove($src . '/.vortex');
 
     $fm->copyFiles();
@@ -433,13 +426,13 @@ public function testCopyFilesRemovesObsoleteScriptsVortex(): void {
     // package ships them instead, so the copy removes the legacy directory.
     $src = self::$sut . '/src_obsolete';
     $destination = self::$sut . '/dst_obsolete';
-    mkdir($src, 0777, TRUE);
-    mkdir($destination . '/scripts/vortex', 0777, TRUE);
-    file_put_contents($src . '/test.txt', 'new');
-    file_put_contents($destination . '/scripts/vortex/legacy.sh', 'legacy');
-    file_put_contents($destination . '/scripts/keep.sh', 'custom');
+    File::mkdir($src);
+    File::mkdir($destination . '/scripts/vortex');
+    File::dump($src . '/test.txt', 'new');
+    File::dump($destination . '/scripts/vortex/legacy.sh', 'legacy');
+    File::dump($destination . '/scripts/keep.sh', 'custom');
 
-    $config = new Config('/tmp/root', $destination, $src);
+    $config = $this->createConfig($destination, $src);
     $fm = new FileManager($config);
 
     $fm->copyFiles();
@@ -451,9 +444,9 @@ public function testCopyFilesRemovesObsoleteScriptsVortex(): void {
 
   public function testRemoveObsoletePathsSilentOnMissing(): void {
     $destination = self::$sut . '/dst_no_obsolete';
-    mkdir($destination, 0777, TRUE);
+    File::mkdir($destination);
 
-    $config = new Config('/tmp/root', $destination, '/tmp/tmp');
+    $config = $this->createConfig($destination);
     $fm = new FileManager($config);
 
     $fm->removeObsoletePaths();
@@ -461,110 +454,63 @@ public function testRemoveObsoletePathsSilentOnMissing(): void {
     $this->addToAssertionCount(1);
   }
 
-  public function testPrepareDemoNotDemoMode(): void {
-    $config = new Config('/tmp/root', self::$sut, '/tmp/tmp');
-    $fm = new FileManager($config);
-
-    $downloader = $this->createMock(Downloader::class);
-    $result = $fm->prepareDemo($downloader);
-
-    $this->assertEquals('Not a demo mode.', $result);
-  }
-
-  public function testPrepareDemoWithFetchSkip(): void {
-    $config = new Config('/tmp/root', self::$sut, '/tmp/tmp');
-    $config->set(Config::IS_DEMO, TRUE);
-    $config->set(Config::IS_DEMO_DB_FETCH_SKIP, TRUE);
-    $fm = new FileManager($config);
-
-    $downloader = $this->createMock(Downloader::class);
-    $result = $fm->prepareDemo($downloader);
-
-    $this->assertIsString($result);
-    $this->assertStringContainsString('Skipping demo database fetch', $result);
-  }
-
-  public function testPrepareDemoNoUrl(): void {
+  /**
+   * @param array<string, bool|null> $config_values
+   *   Config keys to set before preparing, keyed by constant.
+   * @param string|null $dotenv
+   *   Content for the project's '.env', or NULL to write none.
+   * @param bool $with_database_file
+   *   Seed the data directory with an already-fetched database dump.
+   * @param string $expected_message
+   *   Substring the returned messages must contain.
+   */
+  #[DataProvider('dataProviderPrepareDemo')]
+  public function testPrepareDemo(array $config_values, ?string $dotenv, bool $with_database_file, string $expected_message): void {
     $destination = self::$sut;
-    file_put_contents($destination . '/.env', '');
 
-    $config = new Config('/tmp/root', $destination, '/tmp/tmp');
-    $config->set(Config::IS_DEMO, TRUE);
-    $fm = new FileManager($config);
+    if ($dotenv !== NULL) {
+      File::dump($destination . '/.env', $dotenv);
+    }
 
-    $downloader = $this->createMock(Downloader::class);
-    $result = $fm->prepareDemo($downloader);
+    if ($with_database_file) {
+      File::dump(File::mkdir($destination . '/.data') . '/db.sql', 'existing');
+    }
 
-    $this->assertIsString($result);
-    $this->assertStringContainsString('No database fetch URL provided', $result);
-  }
+    $config = $this->createConfig($destination);
+    foreach ($config_values as $name => $value) {
+      $config->set($name, $value);
+    }
 
-  public function testPrepareDemoExistingDatabaseFile(): void {
-    $destination = self::$sut;
-    $data_dir = $destination . '/.data';
-    mkdir($data_dir, 0777, TRUE);
-    file_put_contents($data_dir . '/db.sql', 'existing');
-    file_put_contents($destination . '/.env', "VORTEX_FETCH_DB_URL=https://example.com/db.sql\nVORTEX_DB_DIR=./.data\nVORTEX_DB_FILE=db.sql\n");
+    $result = (new FileManager($config))->prepareDemo($this->createMock(Downloader::class));
 
-    $config = new Config('/tmp/root', $destination, '/tmp/tmp');
-    $config->set(Config::IS_DEMO, TRUE);
-    $fm = new FileManager($config);
+    $messages = is_array($result) ? $result : [$result];
+    $this->assertStringContainsString($expected_message, implode(PHP_EOL, array_map(strval(...), $messages)));
+  }
 
-    $downloader = $this->createMock(Downloader::class);
-    $result = $fm->prepareDemo($downloader);
+  public static function dataProviderPrepareDemo(): \Iterator {
+    $dotenv = "VORTEX_FETCH_DB_URL=https://example.com/db.sql\nVORTEX_DB_DIR=./.data\nVORTEX_DB_FILE=db.sql\n";
 
-    $this->assertIsString($result);
-    $this->assertStringContainsString('already exists', $result);
+    yield 'not a demo' => [[], NULL, FALSE, 'Not a demo mode.'];
+    yield 'fetch skipped' => [[Config::IS_DEMO => TRUE, Config::IS_DEMO_DB_FETCH_SKIP => TRUE], NULL, FALSE, 'Skipping demo database fetch'];
+    yield 'no fetch url' => [[Config::IS_DEMO => TRUE], '', FALSE, 'No database fetch URL provided'];
+    yield 'database already fetched' => [[Config::IS_DEMO => TRUE], $dotenv, TRUE, 'already exists'];
+    yield 'data directory created' => [[Config::IS_DEMO => TRUE], $dotenv, FALSE, 'Created data directory'];
+    yield 'database fetched' => [[Config::IS_DEMO => TRUE], $dotenv, FALSE, 'Fetched demo database'];
   }
 
-  public function testPrepareDemoFetchesDatabase(): void {
+  public function testPrepareDemoDownloadsFromTheConfiguredUrl(): void {
     $destination = self::$sut;
-    file_put_contents($destination . '/.env', "VORTEX_FETCH_DB_URL=https://example.com/db.sql\nVORTEX_DB_DIR=./.data\nVORTEX_DB_FILE=db.sql\n");
+    File::dump($destination . '/.env', "VORTEX_FETCH_DB_URL=https://example.com/db.sql\nVORTEX_DB_DIR=./.data\nVORTEX_DB_FILE=db.sql\n");
 
-    $config = new Config('/tmp/root', $destination, '/tmp/tmp');
+    $config = $this->createConfig($destination);
     $config->set(Config::IS_DEMO, TRUE);
-    $fm = new FileManager($config);
 
     $downloader = $this->createMock(Downloader::class);
     $downloader->expects($this->once())
       ->method('download')
       ->with('https://example.com/db.sql', $this->stringContains('db.sql'));
 
-    $result = $fm->prepareDemo($downloader);
-
-    $this->assertIsArray($result);
-    $this->assertNotEmpty($result);
-
-    $has_download_msg = FALSE;
-    foreach ($result as $msg) {
-      if (str_contains((string) $msg, 'Fetched demo database')) {
-        $has_download_msg = TRUE;
-      }
-    }
-    $this->assertTrue($has_download_msg);
-  }
-
-  public function testPrepareDemoCreatesDataDir(): void {
-    $destination = self::$sut;
-    file_put_contents($destination . '/.env', "VORTEX_FETCH_DB_URL=https://example.com/db.sql\nVORTEX_DB_DIR=./.data\nVORTEX_DB_FILE=db.sql\n");
-
-    $config = new Config('/tmp/root', $destination, '/tmp/tmp');
-    $config->set(Config::IS_DEMO, TRUE);
-    $fm = new FileManager($config);
-
-    $downloader = $this->createMock(Downloader::class);
-    $result = $fm->prepareDemo($downloader);
-
-    $this->assertIsArray($result);
-    $this->assertDirectoryExists($destination . '/.data');
-
-    $has_created_msg = FALSE;
-    foreach ($result as $msg) {
-      if (str_contains((string) $msg, 'Created data directory')) {
-        $has_created_msg = TRUE;
-      }
-    }
-    $this->assertTrue($has_created_msg);
+    (new FileManager($config))->prepareDemo($downloader);
   }
 
   /**
diff --git a/.vortex/installer/tests/Unit/Utils/GitTest.php b/.vortex/installer/tests/Unit/Utils/GitTest.php
index d66c2e605..7a8b6181c 100644
--- a/.vortex/installer/tests/Unit/Utils/GitTest.php
+++ b/.vortex/installer/tests/Unit/Utils/GitTest.php
@@ -35,13 +35,13 @@ public static function dataProviderExtractOwnerRepo(): \Iterator {
   }
 
   public function testInit(): void {
-    $temp_dir = sys_get_temp_dir() . '/git_test_init_' . uniqid();
-    mkdir($temp_dir);
+    $temp_dir = static::$tmp . '/git_test_init_' . uniqid();
+    File::mkdir($temp_dir);
 
     $repo = Git::init($temp_dir);
 
     $this->assertInstanceOf(GitRepository::class, $repo);
-    $this->assertTrue(is_dir($temp_dir . '/.git'));
+    $this->assertTrue(File::isDir($temp_dir . '/.git'));
 
     $this->cleanupTempGitRepo($temp_dir);
   }
@@ -89,8 +89,8 @@ public function testListRemotesWithRemotes(): void {
   }
 
   public function testGetTrackedFilesNonGitDirectory(): void {
-    $temp_dir = sys_get_temp_dir() . '/non_git_' . uniqid();
-    mkdir($temp_dir);
+    $temp_dir = static::$tmp . '/non_git_' . uniqid();
+    File::mkdir($temp_dir);
 
     $this->expectException(\RuntimeException::class);
     $this->expectExceptionMessage('The directory is not a Git repository.');
@@ -152,8 +152,8 @@ public function testGetLastShortCommitId(): void {
    *   Array with temp directory path and Git object.
    */
   protected function createTempGitRepo(bool $with_remote = FALSE, bool $with_commits = FALSE): array {
-    $temp_dir = sys_get_temp_dir() . '/git_test_' . uniqid();
-    mkdir($temp_dir);
+    $temp_dir = static::$tmp . '/git_test_' . uniqid();
+    File::mkdir($temp_dir);
 
     Git::init($temp_dir);
     $repo = new Git($temp_dir);
@@ -163,11 +163,11 @@ protected function createTempGitRepo(bool $with_remote = FALSE, bool $with_commi
       $repo->run('config', 'user.name', 'Test User');
       $repo->run('config', 'user.email', 'test@example.com');
 
-      file_put_contents($temp_dir . '/test.txt', 'test content');
+      File::dump($temp_dir . '/test.txt', 'test content');
       $repo->addAllChanges();
       $repo->commit('Initial commit');
 
-      file_put_contents($temp_dir . '/another.txt', 'another test');
+      File::dump($temp_dir . '/another.txt', 'another test');
       $repo->addAllChanges();
       $repo->commit('Second commit');
     }
@@ -181,7 +181,7 @@ protected function createTempGitRepo(bool $with_remote = FALSE, bool $with_commi
   }
 
   protected function cleanupTempGitRepo(string $temp_dir): void {
-    if (is_dir($temp_dir)) {
+    if (File::isDir($temp_dir)) {
       File::remove($temp_dir);
     }
   }
diff --git a/.vortex/installer/tests/Unit/Utils/JsonManipulatorTest.php b/.vortex/installer/tests/Unit/Utils/JsonManipulatorTest.php
index 5f398fd1f..dc25c87da 100644
--- a/.vortex/installer/tests/Unit/Utils/JsonManipulatorTest.php
+++ b/.vortex/installer/tests/Unit/Utils/JsonManipulatorTest.php
@@ -65,21 +65,21 @@ public function testFromFileWithNonexistentFile(): void {
 
   public function testFromFileWithNonReadableFile(): void {
     $temp_file = $this->createTempJsonFile(self::SAMPLE_JSON);
-    chmod($temp_file, 0000);
+    File::chmod($temp_file, 0000);
 
     try {
       $manipulator = JsonManipulator::fromFile($temp_file);
       $this->assertNull($manipulator);
     }
     finally {
-      chmod($temp_file, 0644);
+      File::chmod($temp_file, 0644);
       File::remove($temp_file);
     }
   }
 
   public function testFromFileWithDirectory(): void {
-    $temp_dir = sys_get_temp_dir() . '/json_test_dir_' . uniqid();
-    mkdir($temp_dir);
+    $temp_dir = static::$tmp . '/json_test_dir_' . uniqid();
+    File::mkdir($temp_dir);
 
     try {
       $manipulator = JsonManipulator::fromFile($temp_dir);
@@ -209,8 +209,8 @@ public function testGetPropertyArrayAccess(): void {
   }
 
   protected function createTempJsonFile(string $content): string {
-    $temp_file = tempnam(sys_get_temp_dir(), 'json_test_');
-    file_put_contents($temp_file, $content);
+    $temp_file = static::$tmp . '/' . uniqid('json_test_');
+    File::dump($temp_file, $content);
     return $temp_file;
   }
 
diff --git a/.vortex/installer/tests/Unit/Utils/NpmLockTest.php b/.vortex/installer/tests/Unit/Utils/NpmLockTest.php
index 58b3d9be1..2a9a392d2 100644
--- a/.vortex/installer/tests/Unit/Utils/NpmLockTest.php
+++ b/.vortex/installer/tests/Unit/Utils/NpmLockTest.php
@@ -167,7 +167,7 @@ public function testSyncWritesTheFileTheWayNpmWritesIt(): void {
 
     NpmLock::sync($manifest_file);
 
-    $contents = (string) file_get_contents(dirname($manifest_file) . '/package-lock.json');
+    $contents = File::read(dirname($manifest_file) . '/package-lock.json');
 
     $this->assertStringContainsString("\n  \"lockfileVersion\": 3,", $contents);
     $this->assertStringContainsString("\n    \"node_modules/keep\": {", $contents);
@@ -182,7 +182,7 @@ public function testSyncPreservesEmptyObjects(): void {
 
     NpmLock::sync($manifest_file);
 
-    $this->assertStringContainsString('"bin": {}', (string) file_get_contents(dirname($manifest_file) . '/package-lock.json'));
+    $this->assertStringContainsString('"bin": {}', File::read(dirname($manifest_file) . '/package-lock.json'));
   }
 
   #[DataProvider('dataProviderSyncThrows')]
@@ -217,7 +217,7 @@ public function testSyncThrowsWhenLockIsNotWritable(): void {
       ['packages' => ['' => ['dependencies' => ['keep' => '^1.0.0']]]]
     );
 
-    chmod(dirname($manifest_file) . '/package-lock.json', 0444);
+    File::chmod(dirname($manifest_file) . '/package-lock.json', 0444);
 
     $this->expectException(\RuntimeException::class);
     $this->expectExceptionMessageMatches('/Unable to write a JSON file/');
@@ -242,7 +242,7 @@ protected function createPair(array $manifest, ?array $lock): string {
   }
 
   protected function readLock(string $manifest_file): array {
-    return (array) json_decode((string) file_get_contents(dirname($manifest_file) . '/package-lock.json'), TRUE, 512, JSON_THROW_ON_ERROR);
+    return (array) json_decode(File::read(dirname($manifest_file) . '/package-lock.json'), TRUE, 512, JSON_THROW_ON_ERROR);
   }
 
 }
diff --git a/.vortex/installer/tests/Unit/Utils/OptionsResolverTest.php b/.vortex/installer/tests/Unit/Utils/OptionsResolverTest.php
index 9e47c3256..7d0cdfb87 100644
--- a/.vortex/installer/tests/Unit/Utils/OptionsResolverTest.php
+++ b/.vortex/installer/tests/Unit/Utils/OptionsResolverTest.php
@@ -8,6 +8,7 @@
 use DrevOps\VortexInstaller\Downloader\RepositoryDownloader;
 use DrevOps\VortexInstaller\Tests\Unit\UnitTestCase;
 use DrevOps\VortexInstaller\Utils\Config;
+use DrevOps\VortexInstaller\Utils\File;
 use DrevOps\VortexInstaller\Utils\OptionsResolver;
 use PHPUnit\Framework\Attributes\CoversClass;
 use PHPUnit\Framework\Attributes\DataProvider;
@@ -125,7 +126,7 @@ public function testResolveWithConfigJsonString(): void {
 
   public function testResolveWithConfigJsonFile(): void {
     $config_file = self::$sut . '/config.json';
-    file_put_contents($config_file, '{"VORTEX_PROJECT_NAME":"file_project"}');
+    File::dump($config_file, '{"VORTEX_PROJECT_NAME":"file_project"}');
 
     $options = self::defaultOptions([
       'config' => $config_file,
diff --git a/.vortex/installer/tests/Unit/Utils/UpdateRegistryTest.php b/.vortex/installer/tests/Unit/Utils/UpdateRegistryTest.php
index b2d3761e0..8cbe95fa1 100644
--- a/.vortex/installer/tests/Unit/Utils/UpdateRegistryTest.php
+++ b/.vortex/installer/tests/Unit/Utils/UpdateRegistryTest.php
@@ -137,4 +137,18 @@ public function testWriteAppendsToExistingRegistry(): void {
     $this->assertFileContainsString($file, '### behat.yml');
   }
 
+  public function testWriteRefusesToReplaceUnreadableRegistry(): void {
+    // A directory at the registry path exists but cannot be read as a file,
+    // which is the condition that would otherwise discard the entries.
+    File::mkdir(self::$sut . '/' . UpdateRegistry::FILE);
+
+    $registry = new UpdateRegistry(self::$sut);
+    $registry->add('phpstan.neon', "level: 5\n", "level: 8\n", "level: 9\n");
+
+    $this->expectException(\RuntimeException::class);
+    $this->expectExceptionMessage('Unable to read the update registry');
+
+    $registry->write('1.40.0', '1.41.0', '2026-09-07 09:31:22');
+  }
+
 }
diff --git a/.vortex/installer/tests/Unit/Utils/VersionTest.php b/.vortex/installer/tests/Unit/Utils/VersionTest.php
index 4312faabc..8a3ca288c 100644
--- a/.vortex/installer/tests/Unit/Utils/VersionTest.php
+++ b/.vortex/installer/tests/Unit/Utils/VersionTest.php
@@ -4,7 +4,7 @@
 
 namespace DrevOps\VortexInstaller\Tests\Unit\Utils;
 
-use AlexSkrypnyk\File\File;
+use DrevOps\VortexInstaller\Utils\File;
 use DrevOps\VortexInstaller\Tests\Unit\UnitTestCase;
 use DrevOps\VortexInstaller\Utils\Version;
 use PHPUnit\Framework\Attributes\CoversClass;
diff --git a/.vortex/installer/tests/Unit/Utils/YamlTest.php b/.vortex/installer/tests/Unit/Utils/YamlTest.php
index 2957f7c61..6cf11bd11 100644
--- a/.vortex/installer/tests/Unit/Utils/YamlTest.php
+++ b/.vortex/installer/tests/Unit/Utils/YamlTest.php
@@ -5,6 +5,7 @@
 namespace DrevOps\VortexInstaller\Tests\Unit\Utils;
 
 use DrevOps\VortexInstaller\Tests\Unit\UnitTestCase;
+use DrevOps\VortexInstaller\Utils\File;
 use DrevOps\VortexInstaller\Utils\Yaml;
 use PHPUnit\Framework\Attributes\CoversClass;
 use PHPUnit\Framework\Attributes\DataProvider;
@@ -19,8 +20,8 @@ public function testValidateFile(string $yaml_content, string $expected_exceptio
       $this->expectExceptionMessage($expected_exception_message);
     }
 
-    $temp_file = tempnam(sys_get_temp_dir(), 'yaml_test_');
-    file_put_contents($temp_file, $yaml_content);
+    $temp_file = static::$tmp . '/' . uniqid('yaml_test_');
+    File::dump($temp_file, $yaml_content);
 
     Yaml::validateFile($temp_file);
 
@@ -51,7 +52,7 @@ public function testValidateFileNonExistent(): void {
     $this->expectException(\RuntimeException::class);
     $this->expectExceptionMessage('File does not exist or is not readable');
 
-    $non_existent_file = sys_get_temp_dir() . '/non_existent_file.yml';
+    $non_existent_file = static::$tmp . '/non_existent_file.yml';
     Yaml::validateFile($non_existent_file);
   }