code: private PropertiesConfiguration loadLanguageConfiguration(String fileOrUrl) {
          PropertiesConfiguration configuration = SwissKnife
                  .loadConfigurationInUtf8(fileOrUrl);
  
          if (configuration != null && ninjaProperties.isDev()) {
              // enable runtime reloading of translations in dev mode
              FileChangedReloadingStrategy strategy = new FileChangedReloadingStrategy();
              configuration.setReloadingStrategy(strategy);
          }
  
          return configuration;
      }
docs: Attempts to load a message file and sets the file changed reloading
  strategy on the configuration if the runtime mode is Dev.