/usr/share/glib-2.0/schemas/25_mate-power-manager-ubuntu.gschema.override is in mate-power-manager-common 1.20.1-2ubuntu1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 | [org.mate.power-manager]
icon-policy='never'
notify-low-capacity=false
|