Hi@PaulLinZ - thanks for the PR!

There are a couple of linting/style failures, can you take a look and fix those while we wait for a maintainer to review the code? You can see that by clicking on "Details" next to the Linting check below, or clicking here:https://github.com/matplotlib/matplotlib/actions/runs/5608270348/job/15193554642?pr=26360

Thanks!

Note that I think what was intended by the issue (and@oscargus can correct me if I'm wrong) was to add such arrow box styles to the library code itself.

This PR adds files to a location that is not part of the library, nor is it included in the documentation as an example, and as such will not be merged in its current state.

Additionally, be advised that there are two existing PRs (#24744 and#24697, both by the same person) which are attempting to resolve the same issue (and do so by adding to the library). In general we prefer to merge the earlier PR when possible. (Though, admittedly, those ones have stalled a bit in a draft state, though the original author has within the last ~month indicated they are interested in picking it back up)

Closing for lack of response and fundamental issues with the implementation. Please feel free to open a new PR or comment on the other PRs addressing this problem if you have other ideas.