--- a/modules/api/GM_xmlhttpRequester.js
+++ b/modules/api/GM_xmlhttpRequester.js
@@ -197,6 +197,14 @@
   if (details[event]) {
     req[event] = function() {
       var responseState = {
+        __exposedProps__: {
+          finalUrl: "r",
+          readyState: "r",
+          responseHeaders: "r",
+          responseText: "r",
+          status: "r",
+          statusText: "r"
+        },
         // can't support responseXML because security won't
         // let the browser call properties on it
         responseText: req.responseText,