The idea of this is to use/abuse ExecCondition=
for a feature similar to the XDG autostart conditions we have.
The program uses the exact same syntax, and the names match up with the relevant systemd merge request (i.e. https://github.com/systemd/systemd/pull/15226).
i.e. this feature could/should simplify a switch to using systemd for XDG autostart files. It could also allow us to retain these conditions for the use with gnome-settings-daemon services.
CC: @aruiz (I guess you might be interested), @iainl
NOTE: I suspect it is unlikely that we will have any actual users before 3.40
. That said, the systemd MR pretty much assumes that this exists already. And it might also be useful to add earlier for developer setups.