Refers to the build layer of Modern.js. The goal of Builder is to provide Modern.js users with out-of-the-box build capabilities and support seamless switching between webpack and Rspack.

The previous version of Modern.js `MAJOR_VERSION.46.0` used `@modern-js/builder`, which was upgraded to [Rsbuild](https://rsbuild.dev/) starting from `MAJOR_VERSION.46.0`.
