> When it is present, WebAuthn attestation tells the site the make and model of the authenticator, identified by its AAGUID, with a certificate chain from the vendor to back it up. It says nothing about your OS, your browser, your extensions, whether your phone is rooted or jailbroken, your firmware version, or even what colour it is.

Am I missing something? "Attestation tells websites what the authenticator is but it doesn't tell the website what the authenticator is".

The entire argument in this blogpost amounts to "nobody would ever turn on passkey attestation because it would require migration of people who already setup passkeys" which is a questionable argument- you could trivially imagine allowing unattested passkeys for existing users, but require it for new users. Most websites don't yet support passkeys to begin with, so this argument doesn't hold for the majority of websites.

The "biggest providers" bit at the end is odd too because the biggest providers are apple/google- who, as far as I know, do support attestation.