Allows users to access Project Server Web sites and Workspaces that have not been added to their trusted internet zones. ...

Allows users to access Project Server Web sites and Workspaces that have not been added to their trusted internet zones. If you enable this setting, users can access Project Server and Microsoft SharePoint Foundation sites that are not in their trusted internet zones. If this setting is disabled or not configured, users are required to add the Project Server and Microsoft SharePoint Foundation sites to their trusted internet site zones.