bug#54296: Add buffer-matching functionality

[Eli Zaretskii]

> From: Philip Kaludercic <philipk@posteo.net>
> Cc: larsi@gnus.org,  54296@debbugs.gnu.org
> Date: Fri, 11 Mar 2022 16:21:06 +0000
> 
> > I think we want in general avoid comparison with major-mode, and
> > prefer derived-mode instead, and if so, IMO we had better did as we
> > say and not exposed comparison to major mode unless we absolutely
> > must.
> 
> Would it be enough to clarify this point in the documentation string?

What would you like to clarify?