I believe the satnav will be able to identify the car of the satnav is pre programmed with the details for example “VIN NUMBER ABC123 is this particular car” but if it doesn’t know the details then it can’t update accordingly
The splash screen and other graphics are already in the satnav, so I believe some check between the car and the satnav is carried out and then it decides what to display
You probably could access the satnav via usb and change images and graphics if you want to manually, on an old tomtom satnav I had you could upload files and images to replace standard ones if you wanted, I assume that’s no different on the blue and me set up, but I’ve never tried