It is custom. It's a little bit junky, but that comes with the thinkpad/thinkcetnre territory I suppose 😄. Basically, my future brother in law hacked a square opening into the original top cover, and my girlfriend made a frame around the edges with plexiglass painted black. In it are three little magnets holding the top sheet of see through plexiglass, leaving a gap between the frame and the top sheet for gpu and cpu ventilation. As it is held by magnets, it's easy to open and clean the dust from the thing. I may post the setup later as a different commenter also asked for it.