FIDO U2F (Bug 1065729) is disabled by default, in favor of W3C Web Authentication. There's significant and ongoing interest in users enabling it via about:config [1][2] (and many more...). It'd be nice for someone to produce a web extension that turned on FIDO U2F support by flipping the "security.webauth.u2f" pref, letting users who are knowledgeable about the limitations of our support use legacy websites. I believe this would be done with a BrowserSetting in similar vein to the websites.resistFingerprinting extension point. [1] https://www.yubico.com/2017/11/how-to-navigate-fido-u2f-in-firefox-quantum/ [2] https://www.reddit.com/r/firefox/comments/7dbcbl/firefox_quantum_comes_with_u2f_support/

:jcj I caught up a bit on U2F and I agree, this makes sense as a browserSetting API for WebExtensions. I'm going to add it to the API backlog.