Are we moving to the Chrome only world?
It also seems to work without UA switcher, but still states it won't work. ¯\_(ツ)_/¯
The console gives this error: "TypeError: m is null".
Edit: another responder to the parent comment said it works for them on Firefox dev edition on Arch Linux. I'm using Nightly on Arch and it gives the message stated above. With a UA switcher set to Chrome Windows, it loads but renders the image strips on the map as black stripes instead of 'textured' ones. Interesting...