LilyPond in Debian

[Urs Liska]

Hi all,

I'm investigating Debian again, looking for a new system for me. So far
I've done a pretty minimal installation of Debian Buster (current
"Testing"), looked for LilyPond and Guile - and was somewhat surprised.

Last time I looked I found that the "lilypond" package had been removed
from Debian Stretch (which has become the current stable release in the
meantime), along with the removal of Guile 1.8.

So I was surprised to see that a lilypond package is again available for
Buster, albeit only 2.18.2. Further investigation turned out that
obviously LilyPond has been reintroduced with Buster, and is also
available in Stretch as a backport (see
https://packages.debian.org/search?keywords=lilypond&searchon=names&suite=all&section=all)

Guile 1.8 on the other hand is not available in Stretch nor Buster - but
in Sid (unstable branch), with the label "debports".

If I'm not mistaken Debian only provides packages that are compiled by
them, so LilyPond can only be included when Guile 1.8 is also present.
So I'm actually wondering how the "lilypond" package could get into
Stretch and Buster.

Could someone with more knowledge update me on this?

Thanks
Urs