Awesome, will rewrite once I hear back.
One constraint -- I'd like to keep backwrd compatibility with Emacs 28
since Emacs 29 is not yet ready for release.
I myself run Emacs from Git@Head
Yes. All three versions will work consistently if you apply the technique of using the arguments passed to your custom member of the eldoc-display-functions hook instead of consulting the internal variable.
IOW the latest refactoring in ElDoc was done in a backward-compatible way.
João