When using Talkback, I'd need to customize the color of the rectangle that appears when a node is Accessibility focused. As I could not find it in settings (unless I really missed it), I downloaded the source code and dived into it, compiling and deploying. But also can't find if it is controlled there (there would be no problem if I had to modify the source since it is for some specific purpose closed-distribution devices, but of course it would be perfect if there were some settings that I have missed)
My main concern is that perhaps I am searching in the wrong direction and simply it is not controlled from an accessibility service, because it is directly related to Android Views (also have reviewed Android View documentation, but could not find anything), or other reasons.
So the question is, can it be customized at any level (OS, Accessibility Service, the same Views..), and if so, how?