[Rauchg]

The way to think about our edge runtime is (which is something you're seeing across the board in the industry) is that there's a pure subset of WinterCG APIs, plus Next.js enabling a compatibility layer on top to play nicely with the _vast_ npm ecosystem.

Everything about the feature you're referring to is open source. We're expanding our documentation to better present this compatibility layer.

[ascorbic]

There's no compatibility layer for AsyncLocalStorage though, and it's not something that can be polyfilled without runtime support. Requiring it in Next.js has forced all the other edge runtimes to implement it in its un-standardised form if they want to support Next.js. Putting it on globalThis is particularly egregious in a runtime that's meant to be standards-compliant and championing the AsyncContext standard. And what about Headers.prototype.getAll()? That's a non-standard method on a standard object that is only implemented by Cloudflare, yet Next.js started using it in a patch release. I get it: you have no incentive to make life easier for other runtimes as used by competitors and AsyncLocalStorage is a really useful API, but people should be under no illusion that you're being a good citizen with the standards here.