Return content on non-delivery?

Applicable protocol:: Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)
Status:: obsolete
Author/Change controller:: IETF (mailto:iesg@ietf.org)
Internet Engineering Task Force.
Specification document(s):: http://www.rfc-editor.org/rfc/rfc1327.txt
Related information:: Indicates whether the content of a message is to be returned with non-delivery notifications. Introduced by RFC 1327, and subsequently changed by RFC 2156 to avoid confusion with MIME defined fields.