manager or system manager can be always set. It would be better to reject
them when parsing config.
+* busctl --user call org.freedesktop.systemd1 /org/freedesktop/systemd1 org.freedesktop.systemd1.Manager GetUnitProcesses "s" run-rbff1b85427b34ba3adf864281aeda8e7.service
+Failed to set address: No such file or directory
+
+ → improve error message
+
External:
* Fedora: add an rpmlint check that verifies that all unit files in the RPM are listed in %systemd_post macros.