[css-borders-4][css-gaps-1] Corner shapes and gap decorations #12150

In MicrosoftEdge/MSEdgeExplainers#985 I got a suggestion for Gap Decorations which made me think of the work being done for border corner shapes:

Awesome proposal! I think it would be lovely to have control over the spacing and styling near intersections. For example, setting a padding on line end to shape how padded lines are before an intersection. Perhaps some combination of border-radius and border-end-end-radius, just so we have an easy and flexible way to add styles to the ends of dividers near intersection would be very useful.

From what I’ve seen, it seems like we could reuse the concepts in corner shape for 3-way and 4-way gap intersections in a grid or other container. Right now, I’m thinking of this as a future-level feature for Gap Decorations, but I wanted to at least put it on the radar as something to think about.