[mattrick]

I believe Gitlab has supported hardware keys for years now. At least Gitlab.com, not sure about the self hosted one.

[doodlesdev]

Also Protonmail supports both U2F and FIDO2. Introduced october last year [0].

[0]: https://proton.me/blog/security-keys

[cvwright]

Yes, but in order to enable it, they require that you enable an app first.

I can only assume that this tactic is usually an attempt to maybe get your phone number, depending on which phone-based method you choose. Which is especially weird for ProtonMail.

[doodlesdev]

It does not require a phone number.

[turnsout]

Fwiw, Gitea now supports WebAuthn!