diff --git a/composer.json b/composer.json
index 172542b1..401dbea4 100644
--- a/composer.json
+++ b/composer.json
@@ -75,12 +75,7 @@
     "minimum-stability": "dev",
     "prefer-stable": true,
     "extra": {
-        "enable-patching": true,
-        "rector": {
-            "includes": [
-                "config/extension.php"
-            ]
-        }
+        "enable-patching": true
     },
     "require-dev": {
         "php": "^8.2",
diff --git a/config/drupal-bootstrap.php b/config/drupal-bootstrap.php
index ba5a930f..f5b24bb3 100644
--- a/config/drupal-bootstrap.php
+++ b/config/drupal-bootstrap.php
@@ -34,4 +34,40 @@
     // need them can re-register this singleton in its own rector.php.)
     $rectorConfig->singleton(DrupalRectorSettings::class, fn () => (new DrupalRectorSettings())
         ->disableBackwardCompatibility());
+
+    // Drupal executes PHP from several non-.php extensions.
+    $rectorConfig->fileExtensions(['php', 'module', 'theme', 'install', 'profile', 'inc', 'engine']);
+
+    // upgrade_status ships intentionally broken test modules.
+    $rectorConfig->skip(['*/upgrade_status/tests/modules/*']);
+
+    // Autoloading and phpstan-drupal only make sense when Drupal is actually
+    // present. Bail out otherwise — DrupalFinderComposerRuntime::getDrupalRoot()
+    // calls Composer\InstalledVersions::getInstallPath('drupal/core'), which
+    // THROWS (not returns null) when the package is not installed, so this must
+    // be guarded before the lookup.
+    if (! \Composer\InstalledVersions::isInstalled('drupal/core')) {
+        return;
+    }
+
+    $drupalFinder = new \DrupalFinder\DrupalFinderComposerRuntime();
+
+    $drupalRoot = $drupalFinder->getDrupalRoot();
+    if (is_string($drupalRoot) && $drupalRoot !== '') {
+        $rectorConfig->autoloadPaths([
+            $drupalRoot.'/core',
+            $drupalRoot.'/modules',
+            $drupalRoot.'/profiles',
+            $drupalRoot.'/themes',
+        ]);
+    }
+
+    // phpstan-drupal lives in the analysed project's vendor dir, not ours.
+    $vendorDir = $drupalFinder->getVendorDir();
+    if (is_string($vendorDir) && $vendorDir !== '') {
+        $phpstanDrupalExtension = $vendorDir.'/mglaman/phpstan-drupal/extension.neon';
+        if (file_exists($phpstanDrupalExtension)) {
+            $rectorConfig->phpstanConfigs([$phpstanDrupalExtension]);
+        }
+    }
 };
diff --git a/config/extension.php b/config/extension.php
deleted file mode 100644
index b84158a0..00000000
--- a/config/extension.php
+++ /dev/null
@@ -1,67 +0,0 @@
-<?php
-
-declare(strict_types=1);
-
-use Rector\Config\RectorConfig;
-
-/**
- * Drupal infrastructure config, auto-loaded for every project that requires
- * drupal-rector ("type": "rector-extension" + "extra.rector.includes").
- *
- * It supplies the Drupal-specific Rector plumbing that otherwise has to be
- * copied into every project's rector.php: the extra PHP file extensions, class
- * import conventions, the upgrade_status skip, Drupal autoloading and (when
- * available) phpstan-drupal.
- *
- * Loading order is: Rector core defaults -> this file -> the project's
- * rector.php. Because the project's config is applied last it always wins:
- * fileExtensions() and autoloadPaths() use "last call wins" semantics, while
- * skip() and phpstanConfigs() are additive. So everything here is a default the
- * project can still override.
- *
- * Imported via $rectorConfig->import(), hence the RectorConfig closure form
- * rather than RectorConfig::configure().
- *
- * NOTE: this deliberately does NOT register config/drupal-phpunit-bootstrap-file.php.
- * That bootstrap throws when it cannot detect a Drupal installation, which would
- * break Rector in any non-Drupal context. The bootstrap is registered by the
- * deprecation sets instead (see \DrupalRector\Set\DrupalSetProvider and the
- * *-all-deprecations sets), which only run against an actual Drupal codebase.
- */
-return static function (RectorConfig $rectorConfig): void {
-    // Drupal executes PHP from several non-.php extensions.
-    $rectorConfig->fileExtensions(['php', 'module', 'theme', 'install', 'profile', 'inc', 'engine']);
-
-    // upgrade_status ships intentionally broken test modules.
-    $rectorConfig->skip(['*/upgrade_status/tests/modules/*']);
-
-    // Autoloading and phpstan-drupal only make sense when Drupal is actually
-    // present. Bail out otherwise — DrupalFinderComposerRuntime::getDrupalRoot()
-    // calls Composer\InstalledVersions::getInstallPath('drupal/core'), which
-    // THROWS (not returns null) when the package is not installed, so this must
-    // be guarded before the lookup.
-    if (! \Composer\InstalledVersions::isInstalled('drupal/core')) {
-        return;
-    }
-
-    $drupalFinder = new \DrupalFinder\DrupalFinderComposerRuntime();
-
-    $drupalRoot = $drupalFinder->getDrupalRoot();
-    if (is_string($drupalRoot) && $drupalRoot !== '') {
-        $rectorConfig->autoloadPaths([
-            $drupalRoot.'/core',
-            $drupalRoot.'/modules',
-            $drupalRoot.'/profiles',
-            $drupalRoot.'/themes',
-        ]);
-    }
-
-    // phpstan-drupal lives in the analysed project's vendor dir, not ours.
-    $vendorDir = $drupalFinder->getVendorDir();
-    if (is_string($vendorDir) && $vendorDir !== '') {
-        $phpstanDrupalExtension = $vendorDir.'/mglaman/phpstan-drupal/extension.neon';
-        if (file_exists($phpstanDrupalExtension)) {
-            $rectorConfig->phpstanConfigs([$phpstanDrupalExtension]);
-        }
-    }
-};