Destinations and Activities may have default Activity Graphs that should be shown when you bring up the Director and are playing in either.

This contract defines the graph referred to and the gating for when it is relevant.
Type: object
Object Properties
Mapped to Definition
The hash identifier of the DestinyActivityGraphDefinition that should be shown when opening the director.
Type: uint32
Mapped to Manifest Database Definition: Destiny.Definitions.Director.DestinyActivityGraphDefinition