--- a/testing/marionette/listener.js
+++ b/testing/marionette/listener.js
@@ -339,17 +339,17 @@ const loadListener = {
     }
   },
 
   observe(subject, topic) {
     const win = curContainer.frame;
     const winID = subject.QueryInterface(Ci.nsISupportsPRUint64).data;
     const curWinID = win.windowUtils.outerWindowID;
 
-    logger.debug(`Received observer notification ${topic} for ${winID}`);
+    logger.debug(`Received observer notification ${topic}`);
 
     switch (topic) {
       // In the case when the currently selected frame is closed,
       // there will be no further load events. Stop listening immediately.
       case "outer-window-destroyed":
         if (curWinID === winID) {
           this.stop();
           sendOk(this.commandID);