COPPER OPENING ON SIDE OF 8830
I think its a simple dumb circuit when you complete the circuit the phone knows its in a holster and uses the holster ring profiles etc..
Imagine in a business environment and you want the phone to be quite when in the holster.
instead of having to turn it on and change settings you PREDEFINE the settings and just shove it in the holster and it changes.
At least thats how I think it works since it has regular and holster settings options and so much have a way of KNOWING when its in the holster. Those contacts seem obvious for it once you see all this.