code: func KnownFeatures(f *FeatureList) []string {
  	var known []string
  	for k, v := range *f {
  		if v.HiddenInHelpText {
  			continue
  		}
  
  		pre := ""
  		if v.PreRelease != utilfeature.GA {
  			pre = fmt.Sprintf("%s - ", v.PreRelease)
  		}
  		known = append(known, fmt.Sprintf("%s=true|false (%sdefault=%t)", k, pre, v.Default))
  	}
  	sort.Strings(known)
  	return known
  }
docs: // KnownFeatures returns a slice of strings describing the FeatureList features.