libgtksourceviewmm is a C++ binding for gtksourceview3.
gtksourceview3 is unmaintained and hasn't had an upstream release for more
than 5 years, so it would be great if the remaining gtksourceview3
applications can move to gtksourceview4 before trixie.
Unfortunately libgtksourceviewmm seems to be dead upstream: the most recent
commit was 3 years ago. It has a branch for porting to gtksourceview4
(https://gitlab.gnome.org/GNOME/gtksourceviewmm/-/tree/gtksourceviewmm-4?ref_type=heads)
but the most recent commit there was 5 years ago, and it never had a stable
release from the gtksourceview4 branch.
Unless there is renewed activity upstream, I think we should plan to
remove this. There are 3 leaf packages that depend on it: cherrytree,
gimagereader and regexxer.
smcv