Don't use $wgTitle here, as it would return an invalid trackback URL for any instance...

diff --git a/includes/Title.php b/includes/Title.php
index 5ef8507..fae7775 100644 (file)
--- a/includes/Title.php
+++ b/includes/Title.php
@@ -3154,10 +3154,10 @@ class Title {
         * @return \type{\string} Trackback URL
         */
        public function trackbackURL() {
-               global $wgTitle, $wgScriptPath, $wgServer;
+               global $wgScriptPath, $wgServer;
 
                return "$wgServer$wgScriptPath/trackback.php?article="
-                       . htmlspecialchars(urlencode($wgTitle->getPrefixedDBkey()));
+                       . htmlspecialchars(urlencode($this->getPrefixedDBkey()));
        }
 
        /**