It was called out in #6901 that the ESM build of this package is really only "faux" ESM; that is, import statements don't use fully-qualified paths with extensions, which is required for runtimes like Node. The addition of "exports" to package.json in #6901 poses a compatibility issue if this package continues shipping faux ESM: this package will be unusable in Node applications that are using native ESM. If one tries to import something like react-bootstrap/Card in such an application, one will see the following error:

Error [ERR_MODULE_NOT_FOUND]: Cannot find module '/.../node_modules/react-bootstrap/lib/ThemeProvider' imported from /.../node_modules/react-bootstrap/lib/Card.js

A workaround would be to directly import the CJS files, e.g. react-bootstrap/cjs/Card.js, but trying to do that on current master fails with the following:

Error [ERR_PACKAGE_PATH_NOT_EXPORTED]: Package subpath './cjs/Card.js' is not defined by "exports" in /.../node_modules/react-bootstrap/package.json imported from /.../index.js

This is expected, but leaves consumers of this package without any option to work around the faux ESM issue.

I'm opening this PR to give folks in this situation an escape hatch: they can explicitly use the CJS build with something like the following:

import Card from 'react-boostrap/cjs/Card'

If you plan on resolving the faux ESM issue before the release of "exports" in package.json, you can safely disregard this PR.