It is called “Filemin” . This is new feature is awesome for server administrator who have difficulty remembering all linux command. Filemin come with complete menu: extract and compress file, copy and paste file, make new file or folder, download and upload, and get file from url and much more.
If you not yet updating your webmin, do it right now and try this new feature.
I think webmin is not cpanel alternative anymore, now Webmin is Cpanel serious competitor.