[dochtman]

I think it is effectively part of/superseded by Web Authentication, which is mentioned and links to:

https://groups.google.com/forum/#!msg/mozilla.dev.platform/t...

First sentence in that thread is "Web Authentication is backward compatible with FIDO U2F second-factor tokens, and also supports more advanced capabilities in future FIDO 2.0 devices."

[dark_ph0enix]

Yup, just came to edit my comment after reading the Web Authentication bit, guess will leave it if anyone has the same question.

[Shoothe]

Yes, WebAuthentication will supersede U2F and it's backward compatible (meaning you can use your Yubikeys, but the API is different).