[dmarc-ietf] Policy Override in aggregate-reporting

[Matthäus Wander <[e-mail]>]

RFC7489 contains a description of the possible PolicyOverrideType 
values: <https://datatracker.ietf.org/doc/html/rfc7489#page-72>

While aggregate-reporting-14 uses the same set of values, the 
description is missing. I suggest to add it back as a new section into 
the main body. "sampled_out" needs an update due to the replacement of 
the "pct" tag. Text suggestion follows.

OLD 2.1.1
There MAY be an element for reason, meant to include any notes the 
reporter might want to include as to why the disposition policy does not 
match the policy_published, such as a Local Policy override (possible 
values listed in Appendix A).

CHANGED 2.1.1
There MAY be an element for reason, meant to include any notes the 
reporter might want to include as to why the disposition policy does not 
match the policy_published, such as a Local Policy override (see Section 
2.1.5).

NEW 2.1.5 Policy Override Reason

The reason element, indicating an override of the DMARC policy, consists 
of a mandatory type field and an optional comment field. The type field 
MUST have one of the pre-defined values listed below. The comment field 
is an unbounded string for providing further details.

Possible values for the policy override type:

    forwarded:  The message was relayed via a known forwarder, or local
       heuristics identified the message as likely having been forwarded.
       There is no expectation that authentication would pass.

    local_policy:  The Mail Receiver's local policy exempted the message
       from being subjected to the Domain Owner's requested policy
       action.

    mailing_list:  Local heuristics determined that the message arrived
       via a mailing list, and thus authentication of the original
       message was not expected to succeed.

    other:  Some policy exception not covered by the other entries in
       this list occurred.  Additional detail can be found in the
       PolicyOverrideReason's "comment" field.

    sampled_out:  The message was exempted from application of policy by
       the testing mode ("t" tag) in the DMARC policy record.

    trusted_forwarder:  Message authentication failure was anticipated by
       other evidence linking the message to a locally maintained list of
       known and trusted forwarders.

Regards,
Matt