LocaleConfigManager::getDefaultConfigLangcode

public LocaleConfigManager::getDefaultConfigLangcode($name)

public function getDefaultConfigLangcode($name) {
  // Config entities that do not have the 'default_config_hash' cannot be
  // shipped configuration regardless of whether there is a name match.
  // configurable_language entities are a special case since they can be
  // translated regardless of whether they are shipped if they in the standard
  // language list.
  $config_entity_type = $this->configManager->getEntityTypeIdByName($name);
  if (!$config_entity_type || $config_entity_type === 'configurable_language'
     || !empty($this->configFactory->get($name)->get('_core.default_config_hash'))
    ) {
    $shipped = $this->defaultConfigStorage->read($name);
    if (!empty($shipped)) {
      return !empty($shipped['langcode']) ? $shipped['langcode'] : 'en';
    }
  }
  return NULL;
}