A potentially very interesting technology, however: the privacy policy and terms are no longer found; and the extension refuses to accept my username.

Documents in the Wayback Machine:

https://web.archive.org/web/20161119084533/http://www.asym.co/privacy/

https://web.archive.org/web/20161119070755/http://www.asym.co/tos/

A shot of the extension failing:

https://s.put.re/gUwhMaHY.png

– that was with Waterfox Classic 2019.10, the same failure occurs with Firefox Quantum 70.0.1.