/usr/share/dbus-1/system-services/com.canonical.applications.Downloader.service is in ubuntu-download-manager 1.2+16.04.20160408-0ubuntu1.
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=com.canonical.applications.Downloader
User=root
Exec=/usr/bin/ubuntu-download-manager
|