Comment 6 for bug 1840677

I think we need either gir1.2-gtksource-3 or gir1.2-gtksource-4 the rest comes in as dependency.
Both will work after the update.

I'll have to ask the desktop Team which is preferred.

Actually this is pretty clear:

apt-cache policy gir1.2-gtksource-3.0 gir1.2-gtksource-4
gir1.2-gtksource-3.0:
  Installed: 3.24.11-1
  Candidate: 3.24.11-1
  Version table:
 *** 3.24.11-1 500
        500 http://archive.ubuntu.com/ubuntu eoan/universe amd64 Packages
        100 /var/lib/dpkg/status
gir1.2-gtksource-4:
  Installed: 4.3.1-2
  Candidate: 4.3.1-2
  Version table:
 *** 4.3.1-2 500
        500 http://archive.ubuntu.com/ubuntu eoan/main amd64 Packages
        100 /var/lib/dpkg/status

v4 is in main, so this is what I will take.
Even no more needed 2.2.1 still makes sense IMHO.