Thanks, the last fetched page on archive.org is from 2025-01-26 [1], removed after this date and before 2025-02-13. 155,477 users at the moment, 1 star reviews were mostly about not working. It's interesting that the developers didn't care to remove the button directing to the ff add-on page at least several months after the removal. Maybe was some kind of PR compromise, they probably thought that listing it with linking to a broken page was better than not listing at all.

A review page [2] mentions that this add-on is a peer-to-peer vpn, not having its own dedicated servers that already makes it suspicious.

[1] https://web.archive.org/web/20250126133131/https://addons.mo...

[2] https://www.vpnmentor.com/reviews/urban-vpn/