diff -u b/core/lib/Drupal/Core/Extension/Extension.php b/core/lib/Drupal/Core/Extension/Extension.php
--- b/core/lib/Drupal/Core/Extension/Extension.php
+++ b/core/lib/Drupal/Core/Extension/Extension.php
@@ -68,6 +68,8 @@
    *   'core/modules/node/node.info.yml'.
    * @param string $filename
    *   (optional) The filename of the main extension file; e.g., 'node.module'.
+   * @param string $name
+   *   The extension name.
    */
   public function __construct($root, $type, $pathname, $filename = NULL, $name = NULL) {
     // @see \Drupal\Core\Theme\ThemeInitialization::getActiveThemeByName()