"Upgrading" the react-native support

Can they? I thought they were strictly static? Do you have a JS example for this?

Improved error messages for manual js/require would be possible since we’d provide a custom require function anyways.

Improving bugsnag errors is unlikely to work since that would require metro support. It might however be possible to do a manual lookup via something like I described here. So maybe something that takes the bugsnag error report, parses it and translates the source locations to CLJS locations where possible.