Final-Recipient

This header field is present in MDN messages (MDN = Message Delivery Notification) The Final-Recipient field indicates the recipient for which the MDN is being issued. The format of the field is: "Address_Type; Email_Address", where Address_Type is (for all practical purposes) equal to "rfc822". The Final-Recipient address may differ from the address originally provided by the sender, because it may have been transformed during forwarding and gatewaying into a totally unrecognizable mess. However, in the absence of the optional Original-Recipient field, the Final-Recipient field and any returned content may be the only information available with which to correlate the MDN with a particular message recipient.

Example:

Final-Recipient: rfc822; matt@chilkatsoft.com