/usr/share/glib-2.0/schemas/10_gsettings-desktop-schemas.gschema.override is in gsettings-desktop-schemas 3.18.1-1ubuntu1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 | [org.gnome.desktop.default-applications.terminal]
exec='x-terminal-emulator'
exec-arg='-e'
|