code: func addBuilderLink(c context.Context, build *ui.MiloBuildLegacy, tags strpair.Map) {
  	bucket := tags.Get("buildbucket_bucket")
  	builder := tags.Get("builder")
  	project := tags.Get("luci_project")
  	if bucket != "" && builder != "" {
  		builderParts := strings.Split(builder, "/")
  		builder = builderParts[len(builderParts)-1]
  		build.Summary.ParentLabel = ui.NewLink(
  			builder, fmt.Sprintf("/p/%s/builders/%s/%s", project, bucket, builder),
  			fmt.Sprintf("buildbucket builder %s on bucket %s", builder, bucket))
  	}
  }
docs: // addBuilderLink adds a link to the buildbucket builder view.