This is a new feature that allows you to link a Location Group with a particular snapshot. Please see the previous help article for more info on how Location Groups work.
Locations Can Be Linked to Multiple Snapshots
This is a problem because a location (sub account) can only exist in one location group inside the Customizer. To fix this, we've added a Conflict Priority number.
This means that if a location is linked to multiple location groups inside the Customizer because they are linked to two or more snapshot IDs, we will link that location to the location group that has the lowest conflict priority (1 being the lowest).