code: func supportsMutableEnvironment(cdir string) (bool, error) {
  	b, err := ioutil.ReadFile(common.Stage1ManifestPath(cdir))
  	if err != nil {
  		return false, errwrap.Wrap(errors.New("error reading pod manifest"), err)
  	}
  
  	s1m := schema.ImageManifest{}
  	if err := json.Unmarshal(b, &s1m); err != nil {
  		return false, errwrap.Wrap(errors.New("error unmarshaling stage1 manifest"), err)
  	}
  
  	_, appRmOk := s1m.Annotations.Get(appRmEntrypoint)
  	_, appStartOk := s1m.Annotations.Get(appStartEntrypoint)
  	_, appStopOk := s1m.Annotations.Get(appStopEntrypoint)
  
  	return appRmOk && appStartOk && appStopOk, nil
  }
docs: // supportsMutableEnvironment returns whether the given stage1 image supports mutable pod operations.
  // It introspects the stage1 manifest and checks the presence of app* entrypoints.