diff --git a/core/lib/Drupal/Component/Plugin/CategorizingPluginManagerInterface.php b/core/lib/Drupal/Component/Plugin/CategorizingPluginManagerInterface.php
index 65578b3..01f7eaf 100644
--- a/core/lib/Drupal/Component/Plugin/CategorizingPluginManagerInterface.php
+++ b/core/lib/Drupal/Component/Plugin/CategorizingPluginManagerInterface.php
@@ -23,7 +23,7 @@ public function getCategories();
   /**
    * Gets sorted definitions.
    *
-   * @param array[]|object[]|null $definitions
+   * @param array[]|null $definitions
    *   (optional) The definitions to sort. If omitted, all definitions are used.
    *
    * @return array[]
@@ -34,12 +34,13 @@ public function getSortedDefinitions(array $definitions = NULL);
   /**
    * Gets definitions grouped by category.
    *
-   * @param array[]|object[]|null $definitions
+   * @param array[]|null $definitions
    *   (optional) The definitions to group. If omitted, all definitions are
    *   used.
    *
-   * @return array[]|object
-   *   An array of plugin definitions, keyed by category and plugin ID.
+   * @return array[]
+   *   Keys are category names, and values are arrays of which the keys are
+   *   plugin IDs and the values are plugin definitions.
    */
   public function getGroupedDefinitions(array $definitions = NULL);
 
diff --git a/core/lib/Drupal/Core/Plugin/CategorizingPluginManagerTrait.php b/core/lib/Drupal/Core/Plugin/CategorizingPluginManagerTrait.php
index 62b5fa7..4450deb 100644
--- a/core/lib/Drupal/Core/Plugin/CategorizingPluginManagerTrait.php
+++ b/core/lib/Drupal/Core/Plugin/CategorizingPluginManagerTrait.php
@@ -35,7 +35,7 @@
    *
    * If the definition lacks a category, it defaults to the providing module.
    *
-   * @param array[] $definition
+   * @param array $definition
    *   The plugin definition.
    */
   protected function processDefinitionCategory(&$definition) {