[OpenID] Confirming XRD CanonicalIDs

[Dan Ragle]

In the specs I read:

    "The Relying Party MUST confirm that the provider of the XRD
     that contains the <CanonicalID> element is authoritative for
     that Canonical ID and that this XRDS document is authoritative
     for the OpenID Service Element. Relying Parties should either
     do this manually or ensure that their resolver does this."

If possible, could someone provide or point me to some lightweight
documentation that elaborates on this, i.e., discusses how such a
confirmation would be manually performed? And does the proxy resolver
at xri.net in fact do this already?

Thanks!

Dan Ragle