diff --git a/core/modules/system/system.module b/core/modules/system/system.module
index d3b55f9..8770abc 100644
--- a/core/modules/system/system.module
+++ b/core/modules/system/system.module
@@ -1163,9 +1163,9 @@ function system_default_region($theme) {
  * for the user by \Drupal\system\Controller\SystemController::compactPage().
  *
  * If the user does not have the cookie, the default value is given by the
- * system variable 'admin_compact_mode', which itself defaults to FALSE. This
- * does not have a user interface to set it: it is a hidden variable which can
- * be set in the settings.php file.
+ * configuration variable 'system.site.admin_compact_mode', which itself
+ * defaults to FALSE. This does not have a user interface to set it: it is a
+ * hidden variable which can be set in the settings.php file.
  *
  * @return bool
  *   TRUE when in compact mode, FALSE when in expanded mode.