I have a micro-proposal:

https://eisenwave.github.io/cpp-proposals/to-string-throws.html

Is it possible to go straight to LWG with this? I don't believe this
is editorial because it does change semantics. It's also not a defect
so seemingly not fit for a mere LWG issue. So I guess it needs to be a
proposal.

However, it would be silly to push this through LEWG-I and LEWG for
months when it's just a tiny wording change.