If you click on "Edit Source Files", you will see some drop-downs.
In addition, I use API's calls to populate the list of libraries that you see when you click on "Manage front-end libraries".
Check out the html file and you will see the code that calls the API's.
You will need to explain more I'm afraid. What are you trying to achieve? In the Node-RED editor, authentication and authorisation are handled internally. If you specify an API on the admin server, you can pass an authentication level that users must possess in order to be able to access the API. Have a look at uibuilder's js file, the API's are defined at the end.
However, you should note a recent thread in the forum about whether or not the admin authorisation works the way it is supposed to as a few of us have experienced odd issues.
