diff --git a/phpBB/phpbb/routing/router.php b/phpBB/phpbb/routing/router.php
index be6660a54b..09c13a371d 100644
--- a/phpBB/phpbb/routing/router.php
+++ b/phpBB/phpbb/routing/router.php
@@ -80,6 +80,11 @@ class router implements RouterInterface
 	 */
 	protected $cache_dir;
 
+	/**
+	 * @var string
+	 */
+	protected $debug_url_generator;
+
 	/**
 	 * Construct method
 	 *