bug#54296: Add buffer-matching functionality

[Eli Zaretskii]

> Date: Wed, 15 Jun 2022 14:48:52 +0300
> Cc: 54296@debbugs.gnu.org, philipk@posteo.net, larsi@gnus.org
> From: Dmitry Gutov <dgutov@yandex.ru>
> 
> On 15.06.2022 05:33, Eli Zaretskii wrote:
> > This seems to be some misunderstanding.  I wanted us to have only
> > 'derived-mode', not 'major-mode'.
> 
> Okay?...
> 
> > But Philip was unhappy about that,
> > due to existing usage of 'major-mode', and eventually 'major-mode' was
> > left in the code.  Or at least this is my recollection of the
> > discussion and its resolution.
> 
> 'major-mode' was left in the code and in the docs, but its meaning was 
> changed. Hence the backward compatibility concern.
> 
> And 'derived-mode' was dropped.
> 
> Or you could say that 'major-mode' was dropped, and 'derived-mode' was 
> left it, but renamed.

Then I'm sorry, but I don't think I have anything to do with that
change.  If I somehow cause Philip to make such changes, I apologize,
because I never meant anything even close (and cannot understand how
what I wrote could have interpreted to that effect, but that's water
under the bridge).

Once again, my only comment about the code was that I thought (and
still think) we should not use major-mode matching, but derived-mode
matching instead.