i used it and liked it

no

The secret key video doesn't work, with error: "No video with supported format and MIME type found." Using latest FF, with uBlock origin turned off. Useless.

If this extension is enabled, when I first started FireFox, there is a significant initial delay to open the first website. I tried to ask the developers about this, but the support e-mail link was useless (returned because they are too busy) and then I tried to use their support community, which requred an account with e-mail verification. I did that, but then when I tried to post a question, there was some sort of stupid rule that I must read 30 posts and read posts 10 minutes. Screw that. I won't read 30 posts to ask about a bug. I am deleting this piece of crap.

good

Ok

Works a bit sloppy.

Edit: firefox deprecated u2f, doesn't work with Ledger anymore