All host names that have been allowed will be listed here.
Glia has restrictions on what host names you are allowed to set for security purposes. It is possible to add host names that are connected to the names you have used previously. For example, if your website is www.xyz.com you can add a host name that says newsite.xyz.com or xyz.com/newsite.
To add a completely new host name please contact your Glia Success Manager.
If you want to develop on a local host see more on that topic here.