What problem does this feature solve?

When there's a patch that hasn't been released yet for a lot of projects, you can reference it using github:org/repo in package.json to pull from the latest commit. Unfortunately, because @rslib/core (and the other packages) are in a monorepo in this repo, that pattern doesn't work so it's quite cumbersome to actually attempt to pull from head temporarily to pull in a patch (the user would have to temporarily vendor it locally, which is very non trivial compared to just a reference)

What does the proposed API look like?

It would be great to have unstable releases published nightly (or even on a per-commit basis), similar to what react does for example