Re: So, it's a PC, right ?
You'll actually just find the GPU mounted on the custom mboard or integrated on the CPU die depending on whether they can cool an integrated version. Never bothered cracking the case of any of mine. While it's barely different from a PC, the underlying hardware graphics access is very different, but hidden by DirectX.
Probably just a matter of time till MS release Win10 for it, they added keyboard support last year and it can run UWP apps. But locked down as possible, of course it will be.