Given their similarities, curious that tipVerticalBelow was moved but tipVerticalAbove wasn't. I guess tipVerticalAbove will be moved in a later diff?

Ah, looks like tipVerticalAbove was deleted in D12984

Any background on why we decided to preserve only one direction of the tips?

For all current use cases we only need an upward facing triangle. I also wanted to remove as much code as possible, to make this easier to refactor. I think once all of this code is refactored, adding the triangle down, if needed, will be easy. And it helps me to have as little logic as possible.

I don't think it makes sense to remove the downwards triangle, given that it's definitely useful in a NUX context. I don't see the point of removing and then re-adding "if needed"

I had already landed some of the code that was removing this logic before I saw this comment (most of the logic related to tooltipLocation was removed in D12942) , so I added a diff at the top of the stack adding this logic back: D13072