Describe your proposed improvement and the problem it solves.

Support the new GFM Alerts (also called admonitions), which look like this:

> [!NOTE]
> This is a note

> [!CAUTION]
> This note cautions you

These could map back to org syntax #+begin_note...#+end_note and similar.

Describe alternatives you've considered.

ox-gfm, but it does not support them and seems unmaintained.