For Access level, leave the This is a private repository box checked.
There are multiple portions to manage, so you'll see a section on agents here along with notes on how to configure the server side components.
Click the file history list to see the committed changes for this file, as shown in the following image.
If this box is unchecked, anyone can see your repository.
This helps ensure that the package itself and the source used to build the package remains the one true source of package metadata.