/usr/share/glib-2.0/schemas/org.gtk.Demo.gschema.xml is in gtk-3-examples 3.10.8-0ubuntu1.
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 13 14 15 16 17 | <?xml version="1.0" encoding="UTF-8"?>
<schemalist>
<enum id='org.gtk.Demo.Color'>
<value nick='red' value='0'/>
<value nick='green' value='1'/>
<value nick='blue' value='2'/>
</enum>
<schema id='org.gtk.Demo' path='/org/gtk/Demo/'>
<key name='color' enum='org.gtk.Demo.Color'>
<default>'red'</default>
</key>
</schema>
</schemalist>
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