diff --git a/core/modules/system/src/Tests/Plugin/Discovery/AnnotatedClassDiscoveryTest.php b/core/modules/system/src/Tests/Plugin/Discovery/AnnotatedClassDiscoveryTest.php
index 76f5aeb..d038dbf 100644
--- a/core/modules/system/src/Tests/Plugin/Discovery/AnnotatedClassDiscoveryTest.php
+++ b/core/modules/system/src/Tests/Plugin/Discovery/AnnotatedClassDiscoveryTest.php
@@ -61,16 +61,16 @@ protected function setUp() {
         'id' => 'big_apple',
         'label' => 'Big Apple',
         'color' => 'green',
-        'class' => 'Drupal\plugin_test_extra\Plugin\plugin_test\fruit\BigApple',
-        'provider' => 'plugin_test_extra',
+        'class' => 'Drupal\plugin_test_extended\Plugin\plugin_test\fruit\BigApple',
+        'provider' => 'plugin_test_extended',
       ),
     );
 
     $base_directory = \Drupal::root() . '/core/modules/system/tests/modules/plugin_test/src';
-    $base_directory2 = \Drupal::root() . '/core/modules/system/tests/modules/plugin_test_extra/src';
-    $namespaces = new \ArrayObject(array('Drupal\plugin_test' => $base_directory, 'Drupal\plugin_test_extra' => $base_directory2));
+    $base_directory2 = \Drupal::root() . '/core/modules/system/tests/modules/plugin_test_extended/src';
+    $namespaces = new \ArrayObject(array('Drupal\plugin_test' => $base_directory, 'Drupal\plugin_test_extended' => $base_directory2));
 
-    $annotation_namespaces = ['Drupal\plugin_test\Plugin\Annotation', 'Drupal\plugin_test_extra\Plugin\Annotation'];
+    $annotation_namespaces = ['Drupal\plugin_test\Plugin\Annotation', 'Drupal\plugin_test_extended\Plugin\Annotation'];
     $this->discovery = new AnnotatedClassDiscovery('Plugin/plugin_test/fruit', $namespaces, 'Drupal\Component\Annotation\Plugin', $annotation_namespaces);
     $this->emptyDiscovery = new AnnotatedClassDiscovery('Plugin/non_existing_module/non_existing_plugin_type', $namespaces);
   }
diff --git a/core/modules/system/tests/modules/plugin_test_extended/plugin_test_extended.info.yml b/core/modules/system/tests/modules/plugin_test_extended/plugin_test_extended.info.yml
index c8bf6cb..f3d0a5b 100644
--- a/core/modules/system/tests/modules/plugin_test_extended/plugin_test_extended.info.yml
+++ b/core/modules/system/tests/modules/plugin_test_extended/plugin_test_extended.info.yml
@@ -1,6 +1,6 @@
-name: 'Plugin Test Extra'
+name: 'Plugin Test Extended'
 type: module
-description: 'Test that plugins can provide plugins and provide namespace discovery for plugin test implementations.'
+description: 'Test annotations can extend other annotations in a different namespace.'
 package: Testing
 version: VERSION
 core: 8.x
diff --git a/core/modules/system/tests/modules/plugin_test_extended/src/Plugin/plugin_test/fruit/BigApple.php b/core/modules/system/tests/modules/plugin_test_extended/src/Plugin/plugin_test/fruit/BigApple.php
index 92cc75a..001e405 100644
--- a/core/modules/system/tests/modules/plugin_test_extended/src/Plugin/plugin_test/fruit/BigApple.php
+++ b/core/modules/system/tests/modules/plugin_test_extended/src/Plugin/plugin_test/fruit/BigApple.php
@@ -2,13 +2,13 @@
 
 /**
  * @file
- * Contains \Drupal\plugin_test_extra\Plugin\plugin_test\fruit\BigApple
+ * Contains \Drupal\plugin_test_extended\Plugin\plugin_test\fruit\BigApple
  */
 
-namespace Drupal\plugin_test_extra\Plugin\plugin_test\fruit;
+namespace Drupal\plugin_test_extended\Plugin\plugin_test\fruit;
 
 /**
- * @PluginExampleExtended(
+ * @PluginExtended(
  *   id = "big_apple",
  *   label = "Big Apple",
  *   color = "green"