If this is populated, this is the activity you have to be playing in order to see this location appear because of this mapping. (theoretically, a location can have multiple mappings, and some might require you to be in a specific activity when others don't)
Mapped to DestinyActivityDefinition in the manifest.
If this is populated, it is the item that you must possess for this location to be active because of this mapping. (theoretically, a location can have multiple mappings, and some might require an item while others don't)
Mapped to DestinyInventoryItemDefinition in the manifest.
The location that is revealed on the director by this mapping.
Mapped to DestinyLocationDefinition in the manifest.
If this is populated, this is an objective related to the location.
Mapped to DestinyObjectiveDefinition in the manifest.
A hint that the UI uses to figure out how this location is activated by the player.