Trigger Action can be used to call any client action in a time span chosen by the developer. The input parameter "Interval" is the number of seconds between the calls and the handler of the "Trigger" event should be the action to call every X seconds.
Refresh Screen can be used to refresh the screen in a time span chosen by the developer. The input parameter "Interval" is the number of seconds between refreshes.
This new version has a visual representation for both tools, making it easier to identify where they're being used in service studio.