docs: @Override
      public Map<String, Object> getParameters(
              HttpServletRequest request, HttpServletResponse response) {
          final LocaleManager localeManager = this.getLocaleManager(request);
  
          final List<Locale> locales = localeManager.getLocales();
          if (locales != null && locales.size() > 0 && locales.get(0) != null) {
              final String locale = locales.get(0).toString();
              final String xslLocale = locale.replace('_', '-');
              this.logger.debug("Setting USER_LANG to {}", xslLocale);
              return Collections.singletonMap("USER_LANG", (Object) xslLocale);
          }
  
          return null;
      }