reverted:
--- b/core/modules/migrate_drupal/src/Plugin/Annotation/MigrateDrupalSource.php
+++ /dev/null
@@ -1,19 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\migrate_drupal\Plugin\Annotation\MigrateDrupalSource.
- */
-
-namespace Drupal\migrate_drupal\Plugin\Annotation;
-use Drupal\migrate\Annotation\MigrateSource;
-
-/**
- * Defines the annotation for Migrate source plugins which deal with Drupal
- * source data.
- *
- * @Annotation
- */
-class MigrateDrupalSource extends MigrateSource {
-
-}