Not working at all in Firefox 81.0.1

Seems to work with Waterfox Classic 2019.12 (below the requirement for Firefox 57.0).

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.

Nice plugin for grabbing performance metrics if your browser has not enough powerful devtools. I use it for TenFourFox build which lacks support of "Performance" tab

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.