Quoting Adam Borowski (kilobyte@???):

> I'd propose giving them some gasoline to burn systemd-shim with. It's a
> tool to run *drumroll* systemd on a system not yet running it as pid 1.

*headdesk*

Um, no.

systemd-shim is/was a third-party Canonical, Ltd. (now apparently orphaned) codebase,
that until recently also had a surviving fork maintained by a Debian
Project package maintainer, that permitted certain GNOME and XFCE
applications such as gnome-shell, that otherwise would require systemd
(because those applications invoke GNOME login and power-management
services), to function without systemd. That secondary fork is now also orphaned.

In the model that systemd-shim supported, GNOME/XFCE talks to
systemd-logind, which talks to systemd-shim (instead of systemd). (Some
KDE4 stuff is also affected.)

My personal solution is: _Don't use_ those particular GNOME/XFCE (and KDE4) codebases.
They have proven to be dependency hairballs, and that is never IMO going
to get fixed.

gnome-shell is not your friend -- but the reason is _not_ it being a
'tool to run systemd on a system not yet running it as PID 1', as that
is simply not the case.