Add description to files in the tree view

Hello,
Tree view: I’m trying to add the description of the files (an unlinkable row below the file title/link) or the excerpt.
Add-on extended shortcode installed.

In the page https://www.wpdownloadmanager.com/wordpress-download-manager-free-v2-2-9-released/ I read:

Additionally we have fixed minor issues with displaying image with file description and category view. Also re-optimized the file list view to make it better looking.

but I can not find a way to add the description parameter
[wpdm_tree download_link=1 description=1]

Should I modify something in the
wpdm-extended-shortcodes/wpdm-extended-shortcodes.php file of the plugin?

In the line 484 line I added description tag

 else
echo "<li  class='file ext_$ext'><a href='" . wpdm_download_url(get_the_ID()) . "' rel='" . wpdm_download_url(get_the_ID()) . "'>" . get_the_title() . "</a>[description]</li>";
            }
        }
        echo "</ul>";
        die();
    }

but clearly it is not supported; where should I add the description parameter?