On start-up some other systems need to be notified that the start-up was successful.
This is a request to allow an interceptor to be defined in the standalone*.xml file that could be called on a successful start-up.
If the startup was unsuccessful ie had any errors the interceptor would not be called.
Whether the startup is successful can be found out by the following cli command
So the information on whether to call the interceptor or not is already known.