Variable: message-ignored-resent-headers
message-ignored-resent-headers is a customizable variable defined in
message.el.gz.
Value
"^Return-receipt\\|^X-Gnus\\|^Gnus-Warning:\\|^>?From \\|^Delivered-To:\\|^X-Content-Length:\\|^X-UIDL:"
Documentation
All headers that match this regexp will be deleted when resending a message.
This variable was added, or its default value changed, in Emacs 24.4.
Source Code
;; Defined in /usr/src/emacs/lisp/gnus/message.el.gz
(defcustom message-ignored-resent-headers
;; `Delivered-To' needs to be removed because some mailers use it to
;; detect loops, so if you resend a message to an address that ultimately
;; comes back to you (e.g. a mailing-list to which you subscribe, in which
;; case you may be removed from the list on the grounds that mail to you
;; bounced with a "mailing loop" error).
"^Return-receipt\\|^X-Gnus\\|^Gnus-Warning:\\|^>?From \\|^Delivered-To:\
\\|^X-Content-Length:\\|^X-UIDL:"
"All headers that match this regexp will be deleted when resending a message."
:version "24.4"
:group 'message-interface
:link '(custom-manual "(message)Resending")
:type '(repeat :value-to-internal (lambda (widget value)
(custom-split-regexp-maybe value))
:match (lambda (widget value)
(or (stringp value)
(widget-editable-list-match widget value)))
regexp))