I'd like to discuss some options, how to improve usability of planned Username-less authentication regarding the UI. @vanrar68 created PR(#7860) for support it; thanks for that, I really like the idea and it'd be great to have it included in Keycloak. I quickly try the solution for that and it seems everything works as expected. However, I've encountered situation, where I think the UI can be better.

I created an authentication flow with Username Password Form and WebAuthn Passwordless Authenticator set up as ALTERNATIVE (for UsernamePwdForm I needed to include it to another flow, because it doesn't support ALTERNATIVE requirement). It means the Username Password Form is displayed to the user and it's possible to be authenticated only by the authenticator, which supports Discoverable credential. The thing is, it'd be great to improve UX within authenticator selection.

Implemented solution in the PR(#7860):

As you can see, when there are some Identity providers defined, the section with the title Or sign in with is present and below the list of IdPs, there is another possibility(Try another way), how to sign in. It doesn't seem to me straightforward and IMHO the Username-less authentication should be on the same level like the Identity providers. And after clicking the Try another way, you're redirected to another page (which seems to me kinda unnecessary).

Proposed solution:

As you can see, there's another item in the list with title Security Key without Username. I think, it'd be a better solution for that.
When there are defined more Identity providers and those items are restructured, the option for the Username-less could be the same like before. Or just edit the title to Security Key and keep the width same like for the IdPs?

@mposolda @vanrar68 @tnorimat WDYT?

EDIT: After discussion below, I agree to keep the design the same as in @vanrar68 approach except for the 'Try another way' link, which should be above the list of Identity Providers.