I am wondering the same thing now that I have looked over the data model. Looks like the dwsystem.DWNotificationSettings table has the notification information, and dwsystem.DWFCNotificationRules has the rules related to those notifications. But I cannot find a linkage to User or Role permissions anywhere...
It would be good to know this, as we periodically run queries to make sure one of our power users (who has some admin privileges) is keeping the App Dev department included in any new notifications created. Otherwise entire task flows are being put into place without us even knowing about it, and we can't always make sure things are making sense from a design perspective.