/usr/share/dbus-1/services/org.xfce.Tumbler.Manager1.service is in tumbler 0.2.1-0ubuntu1.
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.thumbnails.Manager1
Exec=/usr/lib/x86_64-linux-gnu/tumbler-1/tumblerd
|