Recommend RPs to store transport hints

index.bs

@@ -4081,6 +4081,11 @@ In order to perform a [=registration ceremony=], the [=[RP]=] MUST proceed as fo
         in <code>|authData|.[=attestedCredentialData=]</code>, as appropriate for the [=[RP]=]'s system.
     - Associate the <code>[=credentialId=]</code> with a new stored [=signature counter=] value
         initialized to the value of <code>|authData|.[=signCount=]</code>.
+    - OPTIONALLY, associate the <code>[=credentialId=]</code> with the transport hints
+        returned by calling <code>|credential|.{{AuthenticatorAttestationResponse/getTransports()}}</code>.
+        It is RECOMMENDED to use these to populate the {{PublicKeyCredentialDescriptor/transports}}
+        of the {{PublicKeyCredentialRequestOptions/allowCredentials}} option in future {{CredentialsContainer/get()}} calls
+        to help the [=client=] know how to find a suitable [=authenticator=].
 
 1. If the attestation statement |attStmt| successfully verified but is not trustworthy per step 21 above, the [=[RP]=] SHOULD fail
     the [=registration ceremony=].