Codesleeve\Stapler\Attachment::originalFilename PHP Method

    public function originalFilename()
    {
        return $this->instance->getAttribute("{$this->name}_file_name");
    }

 /**
  * Returns the extension of the attached file, e.g 'jpg' for file.jpg.
  *
  * @param Attachment $attachment
  * @param string $styleName
  * @return string
  */
 protected function extension(Attachment $attachment, $styleName = '')
 {
     return pathinfo($attachment->originalFilename(), PATHINFO_EXTENSION);
 }