[dbrgn]

U2F support in Firefox should work out of the box if the developers use the WebAuthn API and not the old JS library: https://hacks.mozilla.org/2018/01/using-hardware-token-based...

[village-idiot]

That was not my experience on google and github.

[jik]

Google and Github both built their U2F support for Firefox before WebAuthn was released, and as you've pointed out, the U2F support in Firefox is gated out by default. Presumably Google, Github, and other companies that coded to U2F will migrate to WebAuthn eventually.