diff --git a/core/modules/migrate/src/Plugin/migrate/process/MenuLinkParent.php b/core/modules/migrate/src/Plugin/migrate/process/MenuLinkParent.php
index 487f6ec..a998067 100644
--- a/core/modules/migrate/src/Plugin/migrate/process/MenuLinkParent.php
+++ b/core/modules/migrate/src/Plugin/migrate/process/MenuLinkParent.php
@@ -15,14 +15,14 @@
 use Symfony\Component\DependencyInjection\ContainerInterface;
 
 /**
- * Determines the menu link parent plugin IDs.
- *
- * The menu_link_parent process plugin figures out menu link parent plugin IDs.
+ * Determines the parent of a menu link.
  *
  * The source is an array of three values:
- *   - parent_id: The parent link ID (plid) is the mlid of the link above in the hierarchy, or zero if the link is at the top level in its menu.
- *   - menu_name: The menu name. All links with the same menu name (such as 'navigation') are part of the same menu.
- *   - parent_link_path: The Drupal path or external path this link points to.
+ *   - parent_id: The numeric ID of the parent menu link, or 0 if the link is at
+ *     the top level of its menu.
+ *   - menu_name: The menu name. All links with the same menu name (such as
+ *     'navigation') are part of the same menu.
+ *   - parent_link_path: The Drupal path or external URL this link points to.
  *
  * Example:
  *
@@ -31,11 +31,16 @@
  *   parent:
  *     plugin: menu_link_parent
  *     source:
- *       - plid
- *       - menu_name
- *       - parent_link_path
+ *       - '20'
+ *       - 'admin'
+ *       - 'admin/structure'
  * @endcode
  *
+ * In this example the parent_id of '20' will be looked up and returned from
+ * amongst the already migrated IDs. If it is not found then the
+ * parent_link_path of 'admin/structure' is loaded from the 'admin' menu, the
+ * given menu_name.
+ *
  * @see \Drupal\migrate\Plugin\MigrateProcessInterface
  *
  * @MigrateProcessPlugin(
@@ -85,24 +90,7 @@ public static function create(ContainerInterface $container, array $configuratio
   }
 
   /**
-   *
-   * Find the parent link GUID.
-   * Performs the associated process.
-   *
-   * @param string $value
-   *   The input string.
-   * @param \Drupal\migrate\MigrateExecutableInterface $migrate_executable
-   *   The migration in which this process is being executed.
-   * @param \Drupal\migrate\Row $row
-   *   The row from the source to process.
-   * @param string $destination_property
-   *   The destination property currently worked on. This is only used together
-   *   with the $row above.
-   *
-   * @return string
-   *   The sub string of $value.
-   *
-   * @throws \Drupal\migrate\MigrateSkipRowException
+   * {@inheritdoc}
    */
   public function transform($value, MigrateExecutableInterface $migrate_executable, Row $row, $destination_property) {
     $parent_id = array_shift($value);