User map script elements
The user map script is an optional way to determine the user name to present to a web application if the other user mapping options won’t provide what’s required. Your script can examine current application and user properties for this user session and can use that information and any other factors to create a user name. The user map script must, at some point, assign a user name to the
LoginUser.Username property, where it’s retrieved later to create a SAML assertion.