That would be good. It could also be improved in the docs just by saying “use an appropriate Python version. See [here] for versions”.
Ideally we should do both. PR to improve the error message is here: Better Python version mismatch errors by hoodmane · Pull Request #142 · pyodide/pyodide-build · GitHub
Where would be a good place to open an issue?
The relevant spot is here.
the pyodide docs focus on JS developers since they are the “users” but maybe there can be a big signpost on the main page or README and perhaps links from some other pages to something that is explicitly aimed at Python package developers
Agreed, we really want to provide information for both audiences. Here’s a start in that direction.