/usr/lib/x86_64-linux-gnu/ubuntu-system-settings/private/Ubuntu/SystemSettings/Background/qmldir is in ubuntu-system-settings 0.1+14.04.20140411-0ubuntu2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 | module Ubuntu.SystemSettings.Background
plugin UbuntuBackgroundPanel
|