Gyrus depends on amtk which has been abandoned upstream (Debian #99393)
This was reported in Debian BTS: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=993931
Source: gyrus Version: 0.3.12-1 Severity: important User: pkg-gnome-maintainers@lists.alioth.debian.org Usertags: oldlibs Control: block 993922 by -1 X-Debbugs-Cc: Yavor Doganov yavor@gnu.org, Jonathan Carter jcc@debian.org
amtk has been frozen and archived upstream, and contributions are no longer accepted. See https://gitlab.gnome.org/Archive/amtk and https://gitlab.gnome.org/Infrastructure/Infrastructure/-/issues/564 for more details.
The versions of gedit and devhelp on GNOME infrastructure stopped using amtk at the same time they stopped using tepl, which is in a similar situation (see #993909). I don't think amtk should be included in Debian 12.
The remaining packages that use amtk (genius, goodvibes and gyrus) will either need to stop using amtk (and switch to making the same calls into GTK that amtk does, but more directly), or fork it. If they fork it, the former maintainer requests that they use a different name.
Note that in the case of this unmaintained Debian package, the use of amtk is a Debian-specific patch (part of the port from GTK 2 to GTK 3) rather than an upstream decision.
smcv