This issue has been fixed. I was using a proxy to grab the raw file from Github via normal http, but recently Github has been defaulted to serve via https, and

This issue has been fixed. I was using a proxy to grab the raw file from Github via normal http, but recently Github has been defaulted to serve via https, and forces all normal http traffic to https with a 301, thus the proxy failed. I updated the code to us https instead so the diff view should be working again.