This package contains lower level utilities that you can use if you are writing a plugin / transform for a bundler or module system that compiles Vue single file components into JavaScript. It is used in [vue-loader](https://github.com/vuejs/vue-loader), [rollup-plugin-vue](https://github.com/vuejs/rollup-plugin-vue) and [vite](https://github.com/vitejs/vite).
The API is intentionally low-level, because different toolings have different constraints on how much context is shared between the transformation of each block in an SFC. For example, the template sub-loader in `vue-loader` may not have access to the full SFC and its descriptor.
The browser build relies on a browser-bundled build of `postcss` to be available under the global `postcss` (since it can't be properly bundled by Rollup).