@matthieum I like the idea of translating those extended errors specifically.
I’m not sure what their fate is though. Part of the recent error message RFC was a mandate to start converting those to dynamic errors as well, which could complicate the picture. I suspect though that the resulting system will be relatively self-contained, in particular defined in templates instead of directly in the code. That could still be relatively easy to internationalize. cc @GuillaumeGomez @jntrnr something to think about.