How can I find a Firefox version that accepts passkeys?

I wouldn't call it experimental, it's just in continuous development.

Try to open https://webauthn.io/ and click Authenticate. The passkey auth window should show up after a while.

I gave that a try. One confusing thing is that when I'm doing Firefox settings, the software continues to tell me that passkeys are not supported in Firefox. On the Webauthn site, I went through the quick process provided on their page. I did this while browsing with Firefox. That process pulled up the Windows Hello face recognition program, which works well for me. So Firefox may not support passkeys, but sites used while browsing with Firefox certainly do.

So as I say, that's confusing. I have no idea what it means.

One other observation. Search for "passkeys" in Firefox settings and the term is not found.

Firefox may not support passkeys, but sites used while browsing with Firefox certainly do.

Trying to grasp the issue; 1. sites used while browsing with Firefox certainly do. 2. But isn't that the purpose of Firefox, to access 'sites'

??

Oh the confusing part might be some other browsers implement Passkey support inside their keystore in custom ways — because, well, some of the browser vendors also own the whole operating systems and the like;) — so they piggyback on their existing credential stores in bespoke ways.

Firefox doesn't store or sync any Passkeys on its own, it only relays the handling between the websites and the (system) key store that's responsible for Passkeys and their storage/access or sync on the platform level.

So you won't actually find anything "Passkey"–related in settings currently — the web platform API standard is called "Webauthn" developer.mozilla.org/docs/Web/API/Web_Authentication_API and is mostly opaque to the users — unless there's an explicit need to change the API surface and tinker with the browser internals, alas.

So basically you mostly wanna check the site operators for support, and your device default credential store for handling — Firefox only passes the messages along using that API above.