/usr/share/dbus-1/system-services/org.freedesktop.PackageKit.service is in python3-aptdaemon.pkcompat 1.1.1-1ubuntu5.2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 | [D-BUS Service]
Name=org.freedesktop.PackageKit
Exec=/usr/sbin/aptd
User=root
|