/usr/share/dbus-1/services/org.freedesktop.PackageKit.service is in gnome-software 3.28.1-0ubuntu4.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 | [D-BUS Service]
Name=org.freedesktop.PackageKit
Exec=/usr/bin/gnome-software --gapplication-service
|