Query ReportServerDB,Table ReportSchedule, Column ReportAction -> Translation needed

does anyone analyzed already the integer column "reportaction" in Table ReportSchedule?
Search engine returned nothing for me...

Here's my translation so far, but i'm missing the integers 1 and 2:

SELECT
 ScheduleID
,ReportID
,SubscriptionID
,ReportAction
,ReportActionName =
 CASE rs.ReportAction  WHEN 4 THEN 'Subscription'  -- represents either datadriven oder user-rcreated subscription
                                  WHEN 3 THEN 'CacheInvalidate' --represents either report or shared-dataset cache retire schedule
                                  ELSE CAST(ReportAction as nvarchar(100))
          END       
FROM ReportServer.dbo.ReportSchedule RS