I was playing with the latest dump1090-mutability version (heywhatsthat panorama range ring support) but had trouble getting the json data from the URL specified in line 501 of the script.js update:
in your url id=XXXX needs to be changed to the ID of the view generated by the heywhatsthat.com site.
Look near the top left corner for the page displaying the view to find the URL of the view then take what’s after ?view= and replace the XXXX with that view ID.