How to make different colors (red, yellow, green) show layers of the screen?

Question

Android

In some articles they write how you can determine how many times the layout is reused by color, but through what do they look at it? I searched everything on the phone, how to enable this function?

Answer 1

I suspect that this is not about reuse, but about overdraw - how many times a drawing occurs on top of another drawing.
Developer options - debug overlays.