message-forward-subject-author-subject
message-forward-subject-author-subject is a compiled Lisp function in `message.el
'.
(message-forward-subject-author-subject SUBJECT)
Generate a SUBJECT for a forwarded message.
The form is: [Source] Subject, where if the original message was mail,
Source is the sender, and if the original message was news, Source is
the list of newsgroups is was posted to.