Split out yaru-theme-gtk2

[Jeremy Bícha]

As suggested in MIR bug 1783600, we would prefer to not have gtk2 in the default install.

Therefore, I recommend splitting out yaru-theme-gtk2 (with its dependencies on the gtk2 theme engines) and then have Ubuntu's libgtk2.0-0 recommend or depend on that package. I prefer it be a Depends, but there may be concerns about circular dependencies.

Other Info
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For now, we still end up needing gtk2 on the ISO because of gparted and 3 input methods.

[Didier Roche-Tolomelli (didrocks)]

Let's triage it for next cycle.

[wontfix (wontfix)]

Many cycles have passed and the GTK2 assets with combined packaging are still in place.
https://git.launchpad.net/ubuntu/+source/yaru-theme/tree/debian/control?h=applied/ubuntu/devel#n41

[wontfix (wontfix)]

>For now, we still end up needing gtk2 on the ISO because of gparted and 3 input methods.

Is this still true? It was originally posted in 2018.

https://gitlab.gnome.org/GNOME/gparted/-/issues/7
https://packages.ubuntu.com/focal/gparted
https://packages.ubuntu.com/focal/ibus-gtk3
https://packages.ubuntu.com/jammy/ibus-gtk4

~$ sudo apt install gparted

~$ sudo apt purge *gtk2*

The following packages will be REMOVED:
  gnome-themes-extra* gtk2-engines-murrine* gtk2-engines-pixbuf* ibus-gtk*
  libgail-common* libgail18* libgtk2.0-0* libgtk2.0-bin* libgtk2.0-common*
  yaru-theme-gtk*

[Jeremy Bícha (jbicha)]

gparted has switched to GTK3, but GTK2 is still a dependency of ibus-chewing and mozc-server. Those are probably not installed on *your* computer but they are included in the ISO.