If a directory on a site does not contain an index file, it default behavior is that it will simply list every file on that directory. This is not something that is always desirable and the index manager allow you to turn this feature off.
Video Tutorial: How to Use the Index Manager
The index manager can stop people from seeing a list of all your files in a folder (the "Index of/" page that appears when you do not have an index.html file.)
- Go to cPanel and click Index Manager.
- Select Web Root or the domain name or subdomain you want to view. Click Go once selected. (Selecting Web Root will allow you to see all the publicly visible folders on your account.)
- Click on a folder icon to look inside. Click on a folder name to change it.
- To disable directory indexing, change the setting to "No Indexing".
- To enable directory indexing, change the setting to anything except "No Indexing".