code folding arrow color

I'd like to know how to change the color of the code folding arrow in the editor. There's a previous question about this from almost ten years ago, and the answer no longer seems correct. I've tried editing the colors for the “tear line” and the “tear line selection”, and they have no effect on the code folding arrow. As an aside, I'd like to see some documentation that explains the various terms under editor/color scheme/General, because they're not always self-evident, and the example panel doesn't always indicate what's being changed.