Re: master 42596bd 2/6: Little improvements in rmail.el. Recognize encryped override headers.

[Eli Zaretskii]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Cc: Eli Zaretskii <eliz@gnu.org>,  rms@gnu.org,  emacs-devel@gnu.org
> Date: Wed, 12 May 2021 17:47:35 +0200
> 
> What if there's users out there that really want to see that [EXTERNAL]
> thing, because their incoming MTA adds it, and it's corporate policy to
> have those markings on mail that arrives from outside?  Suddenly they
> get a stern talking-to from HR.

This is a misunderstanding: the code Richard added doesn't remove
[EXTERNAL] from the Subject line shown to the user, it removes it when
"simplifying" the Subject for the purposes of comparing it to other
Subjects.  IOW, it's an internal removal, not visible to the user.
All the user sees is that Subjects "Foo" and "[EXTERNAL] Foo" compare
equal, just like "Re: Foo" and "Antwort: Foo".  Rmail has a command
rmail-next-same-subject, which uses that.