This is what I could collect from the source and packages:


 GST creates a list of platforms supported by liboobs
(https://packages.debian.org/stretch/liboobs-1-5)
Ref: https://github.com/GNOME/gnome-system-tools/blob/master/src/common/gst-platform-dialog.c#L235
which happens to contain Debian and its derivatives

Workaround: Somehow make modifications in
https://packages.debian.org/stretch/system-tools-backends