addon/helpers/storage.js
function _getNamespace(appConfig, addonConfig) {
  // For backward compatibility this is a opt-in feature
  let namespace = addonConfig.namespace;

  // Shortcut for modulePrefix
  if (namespace === true) {
    namespace = appConfig.modulePrefix
  }

  return namespace;
}
function _getNamespace(appConfig, addonConfig) {
  // For backward compatibility this is a opt-in feature
  let namespace = addonConfig.namespace;

  // Shortcut for modulePrefix
  if (namespace === true) {
    namespace = appConfig.modulePrefix
  }

  return namespace;
}
TODO: v2.0 - Make modulePrefix the default