Super Globals are global variables that can be defined by the user. They are always of type Variant.
They are super globals because they are global across the entire Flow system. A super global can be referenced from another map, or from a different execution of the same map.
Super Globals are naturally Persistent. They are persistent across the entire execution of Flow. Therefore only when Flow or FlowServer is restarted will the super globals be reset.
Care should be taken when using super globals that you don't use the same global for different purposes. It would cause a conflict as to the value you expect within the super global at any one time.
Super Globals are referenced like fields through the special Globals array. Their value can be accessed through the properties .Value, .AsString, .AsInteger, and .AsFloat (Refer to See "Referencing Fields" for information on how these properties work with fields - it is the same for super globals).