only in patch2:
unchanged:
--- /dev/null
+++ b/core/modules/system/tests/modules/menu_test/lib/Drupal/menu_test/Plugin/Menu/LocalTask/TestTasksPlaceholderSub1.php
@@ -0,0 +1,25 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\menu_test\Plugin\Menu\LocalTask\TestTasksSettingsSub1.
+ */
+
+namespace Drupal\menu_test\Plugin\Menu\LocalTask;
+
+use Drupal\Core\Annotation\Menu\LocalTask;
+use Drupal\Core\Menu\LocalTaskBase;
+use Drupal\Core\Annotation\Translation;
+
+/**
+ * @LocalTask(
+ *   id = "menu_local_task_test_placeholder_sub1",
+ *   route_name = "menu_local_task_test_placeholder_sub1",
+ *   title = @Translation("placeholder sub1"),
+ *   tab_root_id = "menu_local_task_test_placeholder_sub1",
+ *   weight = "-10"
+ * )
+ */
+class TestTasksPlaceholderSub1 extends LocalTaskBase {
+
+}
only in patch2:
unchanged:
--- /dev/null
+++ b/core/modules/system/tests/modules/menu_test/lib/Drupal/menu_test/Plugin/Menu/LocalTask/TestTasksPlaceholderSub2.php
@@ -0,0 +1,25 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\menu_test\Plugin\Menu\LocalTask\TestTasksSettingsSub1.
+ */
+
+namespace Drupal\menu_test\Plugin\Menu\LocalTask;
+
+use Drupal\Core\Annotation\Menu\LocalTask;
+use Drupal\Core\Menu\LocalTaskBase;
+use Drupal\Core\Annotation\Translation;
+
+/**
+ * @LocalTask(
+ *   id = "menu_local_task_test_placeholder_sub2",
+ *   route_name = "menu_local_task_test_placeholder_sub2",
+ *   title = @Translation("placeholder sub2"),
+ *   tab_root_id = "menu_local_task_test_placeholder_sub1",
+ *   weight = "-10"
+ * )
+ */
+class TestTasksPlaceholderSub2 extends LocalTaskBase {
+
+}