I just stumbled upon this setting in Accessibility. I've searched and seen nothing on it. Does anybody have an idea what it does? I don't see any difference when it's checked.
Interesting, mine is checked also, I don't recall if I enabled while experimenting or if thats the default.
I investigated further and found its off by default. Apple defines this as;
Differentiate without color -
Use shapes, in addition to or instead of color, to convey status or information.
(from help)
However I still can't find an example of the difference.