/usr/share/glib-2.0/schemas/10_eog.gschema.override is in eog 3.4.2-0ubuntu1.3.
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.eog.ui]
external-editor="shotwell-viewer.desktop"
sidebar=false
|