To close the loop, to their credit, I reached out via email and did get a response. The response however was that they have no instructions yet. The offered to fully refund the cost in exchange for making an installation video if I wanted to.
Net net is that I didn't feel like pulling everything apart to figure out what harness it was intended to tap into, but I did install it and it works great.
I removed the least possible bits and pieces from the dash and decided to use an add-a-circuit to piggy back on the "cigarette lighter" fuse in the panel behind the glove box. Also found a got spot to catch a ground relatively near the console itself so only had to route the positive to the fuse panel.
Finding a decent way to route the wires was not difficult at all, it works perfectly, and you'd never know it didn't come with the car.
Great item if you don't mind some minor disassembly and finding your own way to wire it up.
-2018 Discovery Sport HSE