/usr/share/mate/autostart/ubuntu-mate-welcome-autostart.desktop is in ubuntu-mate-live-settings 18.04.17.
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 10 11 12 | [Desktop Entry]
Version=1.0
Name=Welcome
Comment=Ubuntu MATE Welcome autostart
Categories=
Terminal=false
Type=Application
Exec=/snap/bin/ubuntu-mate-welcome --autostart
OnlyShowIn=MATE;
StartupNotify=false
NoDisplay=true
X-MATE-Autostart-Delay=30
|