Not working at all in Firefox 81.0.1

Doesn't seem to do anything. After the tests of run there's no result screen or anything. There's no documentation and the video has no sound. All in all a pretty poor effort and waste of time.

I am sure that I probably missing something obvious, but I could not figure our how to find/run this extension after installing it. I am running Firefox Developer Edition 58.06.13 (64-bit). I am suspicious of this possibly being a comparability thing.