/usr/share/applications/ubuntu-mate-software.desktop is in ubuntu-mate-welcome 16.04.9.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 | [Desktop Entry]
Terminal=false
Type=Application
Categories=PackageManager;System;Settings;
Name=Software Boutique
Comment=Ubuntu MATE Software Boutique
Exec=ubuntu-mate-welcome --software-only
Icon=system-software-install
StartupNotify=false
|