A package exports both "." and "./reports". What must its declarations cover?

A package exports both "." and "./reports". What must its declarations cover?

1. Only the package root, because TypeScript always reuses its index.d.ts for subpaths.
2. Each public subpath, with types matching that subpath’s runtime target and module format.
3. Only ./reports, because exports disables the package root.
4. No declarations when the JavaScript files use ESM syntax.