It is meant to be used with the Flexible Neon LED strips. 5mm width, 11mm height ones.
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.

TIPs on placing Neon LED inside:
1) do it slowly and gently, as you may end up ruining LED (as seen on the photo);
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.

Creality

Ender 3

No

No

20