How can I make colliders-only visible in Godot?

Question

Specifically, I'm looking for any way to see a collision-only item from a Mesh Library in a GridMap. (The tag says "tile map", which it technically isn't; but there's no option for a grid map and this seems close enough.) There's no mesh to draw, so I'm left guessing, or discovering by trial and error, where it is. Then I make a note and adjust it or remove it before my next run. Clearly this isn't the most efficient way of working.

If I could get the collision meshes alone rendered in the scene, this would make it trivial to use.

Answer 1

Seems I actually can find invisible meshes relatively easily by switching display mode to "Display Overdraw", which is great. There's still a little guesswork as to where to look, but that's no big deal.