Just writing down some considerations based on the fact we're retiring cerbere and switching to gnome-session to manage session components (like plank and wingpanel).

gnome-session >= 3.34 is using systemd units for session components by default and it looks like we're getting that version or newer in 20.04, so we should probably look into this.

Thanks to @quequotion we know that we don't need to use this new systemd method and we can use the --builtin flag on gnome-session to carry on supporting the X-GNOME-AutoRestart key that we're planning to use for 3.28, but maybe systemd will bring us some advantages like more configurable aggressiveness of restarting components etc...

I imagine that the --builtin option will become less and less supported as time goes on, but at least we know we have two options outside of Cerbere for 6.0.

Some info here:

• https://blogs.gnome.org/benzea/2019/10/01/gnome-3-34-is-now-managed-using-systemd/
• https://www.youtube.com/watch?v=pdwi3NWAW7I