18/03/2019
Using Firefox Quantum on 65.0.1 (64 bit).

Doesn't work. Get a notification asking to reload the page. Reload page. Get a notification asking to reload the page. Reload page. Get a notification asking to reload the page. Reload page. Get a notification asking to reload the page. Reload page. etc.

Would not install on a different machine earlier this week (no Elephant icon; no sign of add on in menu).