This is callstack/repack, a monorepo providing a toolkit to replace Metro with Webpack or Rspack for React Native bundling. It delivers a production-grade build pipeline with CLI commands (`start`, `bundle`), a custom Fastify-based dev server with HMR, symbolication, and WebSocket messaging, and over 20 Webpack/Rspack plugins for code splitting, Module Federation (V1/V2), Hermes bytecode compilation, code signing, and asset handling. The architecture is modular: a core `packages/repack` package contains loaders (assets, babel-swc, flow, react-refresh), runtime modules (ScriptManager, Federated helpers), and native Android/iOS code for script loading and code signing. A separate `packages/dev-server` package provides a bundler-agnostic server with delegate interfaces, and first-party plugins for NativeWind, Reanimated, and Expo modules are maintained alongside. The project supports both Webpack 5 and Rspack 1.x/2.x, with extensive integration tests and Metro-compatibility resolver tests. Module Federation is a key feature, enabling micro-frontend architectures in React Native apps with dynamic script loading via the client-side ScriptManager. The codebase is actively maintained with frequent releases, dependency updates, and a well-structured monorepo using pnpm, Turborepo, and Changesets. It demonstrates high craftsmanship in its plugin architecture, WebSocket server design, and source map symbolication, though dual bundler support and multiple Federation plugin versions add some complexity.