This is a File & Folder Viewer Plugin of FTP folder for WordPress sites.
So using the shortcode [library-viewer], you can print the containing folders & files of your library in front-end of a WP site.
With Library Viewer you can display the containing files and the containing folders of a "specific folder" of your (FTP) server to your users in the front-end.
The significant difference from other similar plugins is that:
For more details and use instructions you can read the readme file
If you want extend the functionality of Library Viewer, you can read about Library Viewer Pro