diff --git a/core/lib/Drupal/Core/TypedData/TypedDataManager.php b/core/lib/Drupal/Core/TypedData/TypedDataManager.php
index a609f56..20910f6 100644
--- a/core/lib/Drupal/Core/TypedData/TypedDataManager.php
+++ b/core/lib/Drupal/Core/TypedData/TypedDataManager.php
@@ -92,6 +92,8 @@ public function __construct(\Traversable $namespaces, CacheBackendInterface $cac
    *
    * @return \Drupal\Core\TypedData\TypedDataInterface
    *   The instantiated typed data object.
+   *
+   * @see \Drupal\Core\TypedData\TypedDataManager::create()
    */
   public function createInstance($data_type, array $configuration = array()) {
     $data_definition = $configuration['data_definition'];
@@ -168,10 +170,12 @@ public function create(DataDefinitionInterface $definition, $value = NULL, $name
    * @endcode
    *
    * @param string $data_type
-   *   The data type, for which a data definition should be created.
+   *   The data type plugin ID, for which a data definition object should be
+   *   created.
    *
    * @return \Drupal\Core\TypedData\DataDefinitionInterface
-   *   A data definition for the given data type.
+   *   A data definition object for the given data type. The class of this
+   *   object is provided by the definition_class in the plugin annotation.
    *
    * @see \Drupal\Core\TypedData\TypedDataManager::createListDataDefinition()
    */