docs: public static String filterCssValue(String value) {
      if (EscapingConventions.FilterCssValue.INSTANCE.getValueFilter().matcher(value).find()) {
        return value;
      }
      logger.log(Level.WARNING, "|filterCssValue received bad value ''{0}''", value);
      return EscapingConventions.FilterCssValue.INSTANCE.getInnocuousOutput();
    }