bug#54296: Add buffer-matching functionality

[Dmitry Gutov]

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.