The @rushstack/heft-api-extractor-plugin integrates API Extractor into Rush Stack's Heft build system. It validates TypeScript declarations, generates API reports (API design reviews), and produces .d.ts rollups, ensuring API stability and discoverability. This plugin automates crucial tasks for library maintainers, catching API breaking changes early and streamlining the release process by generating necessary API documentation and declaration files seamlessly within a Heft-managed project.