in ABrowser:1. Type "about:config" (without quotes) into the Firefox address bar and press Enter
2. Search for “u2f”3. Double-click on security.webauth.u2f to enable U2F (or right-click and select Toggle)
There is also an official PPA: https://support.yubico.com/support/solutions/articles/15000010964-enabling-the-yubico-ppa-on-ubuntu
