I see where my confusion lies now, it actually was related to "Prorender for Blender", which is AMD's non-proprietary answer to CUDA, something AMD have been working with the Blender team to develop.

Basically, AMD users need to install "ProRender for Blender", to enable GPU powered rendering that uses the processing cores on the AMD GPU. It also gives you "Full Spectrum Rendering", whatever that is, and from the comments on various YouTube videos, this is AMD's way of crushing CUDA, since it is open and works on both brands of cards.

I get why the Blender team worked with them on it now, lol, smart move Blender (and AMD).

Anyway, haven't tried it yet, but will as soon as the heating work in this place has been done. I'm off to YouTube now to find out what Full Spectrum Rendering is, but for those who are not aware of the GPU thing, here's what you need to install to enable GPU Blender rendering on your AMD card - PR for Blender