Specifying the directory as part of the `repository` field in a `package.json`
allows third party tools to provide better support when working with monorepos.
For example, it allows them to correctly construct a commit diff for a specific
package.
This format was accepted by npm in https://github.com/npm/rfcs/pull/19.
This package uses `process.env.NODE_ENV` but does not transform its usage during bundling like the rest of the React libraries do. This causes issues when `process` is not defined globally.