As Aaron explains in id:"m2vco72tf3.fsf@wal122.wireless-pennnet.upenn.edu"
Using point-max would include the signature in the quoting as well.
It would probably be fairly odd to want to put an MML tag in one’s
signature, but that doesn’t mean that we should break that usage.
We had to use point-max in the 0.11.1 bug-fix release, because the
mark functionality was added post 0.11.
;; properly quote them in the reply. Note that using `point-max'
;; instead of `mark' here is wrong. The buffer may include user's
;; signature which should not be MML-quoted.
- (mml-quote-region (point) (point-max)))
+ (mml-quote-region (point) (mark)))
(defun notmuch-mua-forward-message ()
(message-forward)