Issue #3498073 by nicxvan: Manually convert unversioned_assets_test_library_info_alter

core/modules/system/tests/modules/unversioned_assets_test/src/Hook/UnversionedAssetsTestHooks.php

+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\unversioned_assets_test\Hook;
+
+use Drupal\Core\Hook\Attribute\Hook;
+
+/**
+ * Hook implementations for unversioned_assets_test.
+ */
+class UnversionedAssetsTestHooks {
+
+  /**
+   * Implements hook_library_info_alter().
+   */
+  #[Hook('library_info_alter')]
+  public function libraryInfoAlter(&$libraries, $extension): void {
+    if ($extension === 'system') {
+      // Remove the version and provide an additional CSS file we can alter the
+      // contents of .
+      unset($libraries['base']['version']);
+      $libraries['base']['css']['component']['public://test.css'] = ['weight' => -10];
+    }
+  }
+
+}

core/modules/system/tests/modules/unversioned_assets_test/unversioned_assets_test.module

-<?php
-
-/**
- * @file
- * Helper module for unversioned asset test.
- */
-
-declare(strict_types=1);
-
-/**
- * Implements hook_library_info_build().
- */
-function unversioned_assets_test_library_info_alter(&$libraries, $extension): void {
-  if ($extension === 'system') {
-    // Remove the version and provide an additional CSS file we can alter the
-    // contents of .
-    unset($libraries['base']['version']);
-    $libraries['base']['css']['component']['public://test.css'] = ['weight' => -10];
-  }
-}