Updated (1/22/17) confirming hardware configuration:

It is an Intel Quad Core 1.9 GHz Atom with 4GB of RAM and a 60GB SSD in the US market.  For the rest of the world, if Rear Seat Entertainment is specified, a 160GB SSD is used.  With the 60GB drive, 10GB is configured for user media, the 160GB drive increases that to 110GB of user media storage.

Located under the front left-side seat, here’s the Infotainment Master Controller (IMC):

Intel article detailing their in-vehicle infotainment (IVI) reference design and their help with InControl Touch Pro

Their reference design for IVI:

Jaguar Land Rover likes to point out that InControl Touch Pro uses an Intel quad-core processor.  Looking at Intel’s IVI documentation, the processor they’re describing is most likely the 1.91Ghz Intel Atom E3845.  A hardened SOC that can operate from -40° to 110°C.

Throughout other articles Linux is referenced and while they may just be using the template for the VM they used in testing some of their new tech, one of the press photos calls out 64-bit Ubuntu.

First the image of the test system running on the additional touch screen.  Then see the second picture below, zooming in on the test screen

This wasn’t a secret, as far back in 2013 they said it would be a GENIVI-compliant, Linux-based infotainment system.