The sound preference is a stock Android "sound picking preference" and whatever list it comes up with is determined by the firmware and whatever is installed on the device.
I'm attaching a couple of screenshots from my Galaxy Nexus - you can see that some apps can get into the list when picking a sound, in this case, it's Solid Explorer.
As for the sound type, it definitely is set inside the XML file as android:ringtoneType="notification"