I sent that in. The reason it looks so knackered is because, to get one for free, I asked for one they were going to throw out.
The port covers normally have two parts - the flexible rubber you see forms the hinge and seal, and a second bit of plastic keeps it rigid and forms a latch. Those were taken as spares to keep other units running. The same goes for every other part that could be removed for reuse
The yellow buttons on the back are user-configurable. We had them both set up for 'scan barcode'. Several of the buttons on the front are also configurable - we had them set to zoom the sat nav, and switch between the satnav and the order-tracking program.
There are two batteries - but surprisingly, you need them both in for it to operate. I'm not sure why they didn't use a single battery.
Some of the connectors are probably because there are options missing - you could get it configured with a camera, an RFID reader and a fingerprint reader; you could also lose the 3G, GPS and barcode scanner. I think there were also options for CPU and RAM.
The docking connector could be used two ways - either for docking, or to screw an accessory onto the bottom. At the bottom of
http://notebookitalia.it/tablet-notebook-panasonic-toughbook-toughpad-2012-14775 you can see one with fitted with the "CF-U1 PIMD" magstripe reader. The grounded screw holes on the bottom were for such accessories to screw into.
List price when they were introduced in 2008 was "starting at $2500" according to
https://gizmodo.com/5019515/panasonic-toughbook-cf-u1-pricing-and-specs-of-the-rugged-little-intel-atom-umpc and subsequently there were minor revisions to support Windows 7. The price dropped as it got older - but Panasonic knew customers didn't have a BATNA without a lot of software rework, so it never got seriously cheap. You can pick them up used on ebay for $100 but not in enough volume to run a business on
When it was introduced the level of integration was pretty cutting edge - smartphones weren't yet in everyone's pockets, Android hadn't even been released, and the iPhone 1 didn't support apps, GPS or 3G. Anyone who thinks they need something like the U1 these days should probably do an Android app instead and get hardware that's smaller and cheaper at the same time