/usr/share/dbus-1/services/com.canonical.certification.PlainBox1.service is in checkbox-ng-service 0.3-2.
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=com.canonical.certification.PlainBox1
Exec=/usr/bin/checkbox service
|