That's no moon! 1.go

if filepath.Ext(mf.path) == ".json" {

  // Unmarshal the YAML instead of directly marshaling to JSON to support future changes of kustomizationFile::marshal method:
  k := make(map[string]interface{})
  err := yaml.Unmarshal(data, &k)
  if err != nil {
    return err
  }

  // Remove `kind` and `apiVersion` so as make minimal changes to original source file:
  delete(k, "kind")
  delete(k, "apiVersion")

  data, err = json.MarshalIndent(k, "", "  ")
  if err != nil {
    return err
  }
}