Exclude all platform authenticators that use self attesation from hav…

…ing to use none attestation

index.bs

@@ -2175,7 +2175,7 @@ a numbered step. If outdented, it (today) is rendered as a bullet in the midst o
                             :   {{AttestationConveyancePreference/none}}
                             ::  Replace potentially uniquely identifying information with non-identifying versions of the
                                 same:
-                                  1. If the [=authData/attestedCredentialData/aaguid=] in the [=attested credential data=] is 16 zero bytes, <code>|credentialCreationData|.[=attestationObjectResult=].fmt</code> is "packed", and "x5c" is absent from <code>|credentialCreationData|.[=attestationObjectResult=]</code>, then [=self attestation=] is being used and no further action is needed.
+                                  1. If the [=authData/attestedCredentialData/aaguid=] in the [=attested credential data=] is 16 zero bytes or |authenticator| is a [=platform authenticator=], <code>|credentialCreationData|.[=attestationObjectResult=].fmt</code> is "packed", and "x5c" is absent from <code>|credentialCreationData|.[=attestationObjectResult=]</code>, then [=self attestation=] is being used and no further action is needed.
                                   1. Otherwise:
                                       1. Set the value of <code>|credentialCreationData|.[=attestationObjectResult=].fmt</code> to "none", and set the value of <code>|credentialCreationData|.[=attestationObjectResult=].attStmt</code> to be an empty [=CBOR=] map. (See [[#sctn-none-attestation]] and [[#sctn-generating-an-attestation-object]]).
                                       1. If |authenticator| is not a [=platform authenticator=] then replace the [=authData/attestedCredentialData/aaguid=] in the [=attested credential data=] with 16 zero bytes.