Hi Alejandro,

quoted

Is such a document only considered useful for business/marketing purposes?

Mostly.

quoted

Isn't there some value in it also for regular users and developers?

The documentation for each API usually documents the implementation-
defined behavior, and differences to other systems.  We don't have it
centralized in a single document, but we have something.

While I don't see much usefulness for myself as a user in having a
centralized document for that, ...

OK, so let's discard the idea of a centralized document, and document it
where appropriate. Documenting it in individual package documentations
is also easier for our community.

quoted

Will there be some effort to create such a document for the upcoming
POSIX.1-2024 standard, for Linux and the GNU libraries and tools?

Heh, I suppose not, unless some company sponsors it, or some individual
feels a strong need for it.  But just guessing.

I agree; there is no reason why anyone should make this effort in 2024
after it wasn't done in 2018.

In the Linux man-pages project I'm documenting differences with POSIX or
the BSDs in the VERSIONS section (see man-pages(7)); sometimes in
CAVEATS, if it's a tricky detail; it depends.

Thanks for the pointer.

VERSIONS or STANDARDS (previously: CONFORMING TO) appear adequate for
documenting implementation-defined behaviour.

For texinfo documentation, I guess it will be up to the individual package
maintainer.

Bruno