code: func ValidBrowsers() []string {
  	keys := make([]string, 0, len(manifestPath[runtime.GOOS]))
  	for k := range manifestPath[runtime.GOOS] {
  		keys = append(keys, k)
  	}
  	sort.Strings(keys)
  	return keys
  }
docs: // ValidBrowsers are all browsers for which the manifest can be currently installed