eXtplorer is a php file manager that gives you browser-based access to your server's filesystem. Its official website is http://extplorer.sourceforge.net/.
Installing the addon
eXtplorer is available as an addon. To install:
cd /usr/games/minecraft/addons ./extplorer.sh
Viewing the stats page
Point your browser to https://ip-address/admin/extplorer/index.php
The default username:password is admin:admin and you will be prompted to change it upon your first login.