Unknown extra under drivers seat

[bluebro]

I've been getting an irritating squeak from the rear quarter panel area recently and decided to remove the rear panel to see if I could fix it.

Behind the panel I found a small magnetised box stuck to the metal skeleton with a motorola symbol on it and traced another wire running up the B pillar toward the roof where it just came to a stop.

Then traced both wires down under the drivers seat and under the carpet were 2 metal boxes stuck to the floor and what looks like a battery pack which then was wired to the main loom running down the drivers side.

There are no manufacturer details on either of the metal boxes or battery.

Any ideas what this could be? It's clearly aftermarket.