Firefox supports them too, but it has to be enabled. https://support.yubico.com/support/solutions/articles/15000017511-enabling-u2f-support-in-mozilla-firefox h

Firefox supports them too, but it has to be enabled. https://support.yubico.com/support/solutions/articles/15000017511-enabling-u2f-support-in-mozilla-firefox https://support.yubico.com/support/solutions/articles/150000... I've run into one important (investment brokerage) site does user-agent sniffing and dropped immediately to calling your registered phone number instead of letting Firefox continue to use the Yubikey that it does actually support.