zimoun <zimon.toutoune@gmail.com> writes:

> Apparently, there is different fonts on master and core-updates, if yes why?

The only known difference since the core-updates merge is that
applications using Pango (e.g. GTK+) no longer recognizes bitmap fonts.

  https://gitlab.gnome.org/GNOME/pango/issues/386

> I mean, on my machine -- Guix on the top of Debian with font-dejavu
> installed -- why does commit 4bdf4182fe (core-update merge) not
> display correctly and the parent commit c81457a588 too but the other
> parent commit 23a59b180b displays nicely?

Leo reported problems with fonts on Debian in
<https://issues.guix.gnu.org/issue/41132>, but said that fonts installed
with Guix still worked.  I don't know what could cause it to fail on
your system.