Firstly, this resolves the confusion of which version of npm to choose from for development.

Secondly, this won't break anything per se, the devEngines field is a way to define the runtime and package manager for developing a project. It actually acts as safegaurd, synonymous to what .nvmrc or shell.nix tries to accomplish.

Eventually, contributors will be relying on these fields to auto setup their environment once it gets adopted in the ecosystem.

I would prefer to wait a few years before this becomes an actual standard. From what I can tell, this is bleeding-edge, speculative, and not even implemented yet. Graphite's dev environment prescribes specific tools and doesn't intentionally support using yarn/pnpm/etc. anyways. Feel free to bring this up again once this becomes a widely adopted standard and including this solves an actively encountered pain point. Thanks.