Nette\Forms\Controls\UploadControl::getHtmlName PHP Method

    public function getHtmlName()
    {
        return parent::getHtmlName() . ($this->control->multiple ? '[]' : '');
    }

 /**
  * @return string
  */
 public function getHtmlName()
 {
     return parent::getHtmlName() . '[]';
 }