code: public static function getDayName($day)
      {
          if ($day < self::DOW_MONDAY || $day > self::DOW_SUNDAY) {
              return '';
          }
  
          $dayNames = [
              self::DOW_MONDAY => self::poorManTranslate('fts-shared', 'Monday'),
              self::DOW_TUESDAY => self::poorManTranslate('fts-shared', 'Tuesday'),
              self::DOW_WEDNESDAY => self::poorManTranslate('fts-shared', 'Wednesday'),
              self::DOW_THURSDAY => self::poorManTranslate('fts-shared', 'Thursday'),
              self::DOW_FRIDAY => self::poorManTranslate('fts-shared', 'Friday'),
              self::DOW_SATURDAY => self::poorManTranslate('fts-shared', 'Saturday'),
              self::DOW_SUNDAY => self::poorManTranslate('fts-shared', 'Sunday'),
          ];
  
          return $dayNames[$day];
      }
docs: Get day name in current language
  
  @param int $day Day of week number according to Tools::dow()
  
  @return string Localised day name
  @static