Add an 'experimental' flag

phantomas_custom/modules/windowPerfYLT/windowPerfYLT.js

@@ -62,7 +62,10 @@ exports.module = function(phantomas) {
                         phantomas.log('Performance timing: document reached "DOMContentLoadedEnd" state after %d ms', time);
 
                         phantomas.pushContext({
-                            type: 'domContentLoadedEnd'
+                            type: 'domContentLoadedEnd',
+                            callDetails: {
+                                arguments: ['(experimental, not reliable)']
+                            }
                         });
                     }, 0);