It is meant to be used with the Flexible Neon LED strips. 5mm width, 11mm height ones. You can see it on one of the photos.

Model does not have specified holes for cable management. You can drill it or burn through. Reason is that I had no idea how to do it while I was drawing a concept and it didn't seem to be that much of a thing. If there are ideas, I maybe changing the model. Circles on the back are the reinforcements of some kind and areas wide enough to adhese it to other object. Then again, there is no hook to use with nail, but this thing is better to be hanged with some creative way, say some threads or  ribbon.

TIPs on placing Neon LED inside:
1) do it slowly and gently, as you may end up ruining LED (you can see “dead” zones on photo. ); Never got to make another picture after fix as printed models were snatched away XD
2) after doing cable management and placing LED inside, glue the holes cables go through. If this thing is about to hang somewhere for a long time, making sure accidents won't happen is a good idea.

Sorry, A1 mini users, i would have to rework model later if there will be requests. For now, just scaling it down might not work if you wont fint thinner Neon LED strips.

If you have some cool outlines to do, let me know. Maybe I would try them too!