U2F: Allow using U2F in Chrome for Android
Currently, I get a message that U2F is only supported in Desktop Chrome. However, with the Google Authenticator app installed, it is possible to use a NFC-enabled U2F token (like the Yubikey neo) to authenticate in Chrome for Android. This works flawlessly with GitHub, for example.
Semi-separate UX complaint: I'm not entirely sure why the "Login via U2F device" button is there, anyway - why do I have to press it instead of it just not needing to be there? Couldn't you just activate the listener for U2F all the time on that page, so that I can either use the U2F device or enter a TOTP code? The "submit" button similarly feels unnecessarily clunky, autosubmit on successful U2F would be nicer.