The Web Authentication spec recently added the authenticator attachment as a field on the returned credential to the spec here: https://github.com/w3c/webauthn/pull/1668
Created attachment 449984 [details]
Committed r288622 (246441@main): <https://commits.webkit.org/246441@main>
All reviewed patches have been landed. Closing bug and clearing flags on attachment 449984 [details].