[sebk]

It's surprisingly difficult to figure what what a passkey is, precisely. I think there's a bit of a terminology issue.

FIDO marketing materials talk about passkeys in the same way you do, a resident key (now called discoverable credentials). Some other materials say that passkey with no other qualifier is a multi-device passkey, meaning it's backed up by a sync fabric. (e.g. the short version here https://passkeys.dev/docs/reference/terms/#passkey). Others, like Google did in their blogpost last week and the long version of that link, say that a passkey is a multi-device passkey that also has user verification (so it can be used for passwordless and not just 2FA/2SV).