diff --git a/core/lib/Drupal/Core/Routing/NullGenerator.php b/core/lib/Drupal/Core/Routing/NullGenerator.php
index d9bc9b0..6a1c6bc 100644
--- a/core/lib/Drupal/Core/Routing/NullGenerator.php
+++ b/core/lib/Drupal/Core/Routing/NullGenerator.php
@@ -29,6 +29,14 @@ public function __construct(RequestStack $request_stack) {
    *
    * generate(), generateFromRoute(), and getPathFromRoute() all call this
    * protected method.
+   *
+   * Available names:
+   * - <front>: The special path that links to the default front page.
+   * - <current>: The special path that links to the current page.
+   * - <none>: The special path that make links relative to the current URL.
+   * 
+   * @param string $name
+   *   String of routing paths.
    */
   protected function getRoute($name) {
     if ($name === '<front>') {