code: func DebugBuild(c context.Context, relBuildbotDir string, builder string, buildNum int) (*ui.MiloBuildLegacy, error) {
  	fname := fmt.Sprintf("%s.%d.json", builder, buildNum)
  	// ../buildbot below assumes that
  	// - this code is not executed by tests outside of this dir
  	// - this dir is a sibling of frontend dir
  	path := filepath.Join(relBuildbotDir, "testdata", fname)
  	raw, err := ioutil.ReadFile(path)
  	if err != nil {
  		return nil, err
  	}
  	b := &buildbot.Build{}
  	if err := json.Unmarshal(raw, b); err != nil {
  		return nil, err
  	}
  	return renderBuild(c, b, true), nil
  }
docs: // DebugBuild fetches a debugging build for testing.