You can in the browser!
Just activate u2fsomething in the about:config.
Edit: it think it is āsecurity.webauth.u2fā
BTW: I was trying to get GitHub - Yubico/yubikey-manager: Python library and command line tool for configuring any YubiKey over all USB interfaces. packed into chum. But I was lost in dependencies (and Iām very inexperienced in packaging.) That would be very nice to have on the phone, then we could use the OATH as well and probably build a GUI for it.
EDIT2: Somehow I think I missed your question. You do not want to login to something in the browser or whatever with the key, but you want to log in to SFOS with the Key! Yeah, that would be nice, too!