code: func embeddedPackages() map[string]interpreter.Loader {
  	perRoot := map[string]map[string]string{}
  
  	for path, data := range generated.Assets() {
  		chunks := strings.SplitN(path, "/", 2)
  		if len(chunks) != 2 {
  			panic(fmt.Sprintf("forbidden *.star outside the package dir: %s", path))
  		}
  		root, rel := chunks[0], chunks[1]
  		m := perRoot[root]
  		if m == nil {
  			m = make(map[string]string, 1)
  			perRoot[root] = m
  		}
  		m[rel] = data
  	}
  
  	loaders := make(map[string]interpreter.Loader, len(perRoot))
  	for pkg, files := range perRoot {
  		loaders[pkg] = interpreter.MemoryLoader(files)
  	}
  	return loaders
  }
docs: // embeddedPackages makes a map of loaders for embedded Starlark packages.
  //
  // Each directory directly under go.chromium.org/luci/lucicfg/starlark/...
  // represents a corresponding starlark package. E.g. files in 'stdlib' directory
  // are loadable via load("@stdlib//<path>", ...).