only in patch2:
unchanged:
--- /dev/null
+++ b/core/modules/migrate_drupal/src/Plugin/Annotation/MigrateDrupalSource.php
@@ -0,0 +1,19 @@
+<?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 {
+
+}