WebAuthn supports sending an attestation certificate during the initial registration. But with an implementation according to the spec this certificate only identifies the model of the security key used and thus is shared across a 5 to 6 digit number of physical keys.
This attestation is meant to allow the service to verify that you use a "blessed" security key with certain security properties (e.g. only a YubiKey 5 they verified to be secure and not some random $5 key with broken RNG off Amazon).