There are seven files here, 400.shtml, 401.shtml, 403.shtml, 404.shtml, 500.shtml, robots.txt and favicon.ico that are default error pages and files for your account. When someone types a URL to your domain and it's wrong, or the page has moved the server will forward to these error pages. 

They can be edited/replaced by you anyway you like. Leaving them here in some form would be preferred.

The index.html can and should be removed once you have a site loaded into this public_html directory.

The robots.txt and favicon.ico files.
If you do not have these files on the server, your site generates small errors every time someone visits. You can view your error logs at any time using the "Error Log" link in your cPanel to keep track of errors as they might come up. These default files are only to get you started and prevent errors from being generated from your account.


If you have any questions on these, please visit our forums at http://siteshostedby.info.
We'll be glad to help you get started with your site.

Infopro