Are we dealing with browser/bundler compatibility or not?

[bmeck]

It seems the PRs on https://github.com/nodejs/ecmascript-modules have multiple voices making claims that we need to do something for web/bundler compatibility and others claiming web/bundler compatibility to be in scope. Sometimes this appears to be the same person. We should solve for this question I think before landing PRs.

[bmeck]

This can be done on a per phase basis.