Passkey is some sort of specific unique key to a device allowing to use a pin on a device instead of the password. But which won’t work on another device.
Now I don’t know if that key can be stolen or not, or if it’s really more secure or not, as people have really unsecure pins.
The main point is all those attacks need to attack the local software or hardware implementation on one of the two ends (or a cert issuer), and even then it’s replay protected so for example an XSS attack lasts only for one session, so it’s more robust.
Removed by mod