The ST6500 today only supports the Web API functionality. This means writing your own code to use HTTP requests or websockets to access read only variables/alarms. Still a web server but not for generic web page access.
When we offer version 3.2, which is expected in early 2021, you will be able to connect using a regular web browser and view the HMI screens using the Web GUI (Graphic User Interface) in synchronous mode. Full read/write access should be available.