While webauthn.io demo works with platform authenticator and required user verification in nightly, PublicKeyCredential.isUserVerifyingPlatformAuthenticatorAvailable() returns false. I'd expect it to return true. Is this a known thing?

Nightly 210305 17:01 (Build #2015796939)
AC: 74.0.20210305144553, 58cfb6476
GV: 88.0a1-20210302034602
AS: 72.1.0

Orignally posted in fenix#18346.

Hi Jon, can you help us prioritise this by telling us what the result of this bug is and what the Fenix priority is?

Hi Emily. I'm the original reporter of this issue at Fenix. I can tell you about the impacts of this issue: my web app calls PublicKeyCredential.isUserVerifyingPlatformAuthenticatorAvailable() in order to check if the device for example supports login via fingerprint. If this returns false, no fingerprint login settings are displayed for the user. That means we cannot offer the possibility of a secure and easy login into our web app. That means, even when Firefox supports WebAuthn, it is not usable for the user due to this bug.

Thanks for following up Urs!

https://hg.mozilla.org/mozilla-central/rev/fe4caa58b249

You can test this by opening https://psteniusubi.github.io/webauthn-tester/credential-create.html and checking the value, currently on the second line.