OptionalscatterOptionalscatterShape recipes and material behaviour the scatter descriptors' assetIds refer to.
OptionalterrainOptionalliquidOptionalresourceResource types the map's cellData resource entries refer to.
OptionalfactionsFaction roster the map's cellData ownership entries refer to.
The descriptor sets that can travel inside a JSON map, so a saved map is self-describing: whatever the cells reference — terrain indices, liquid ids, scatter assets, resource types, faction ids — is defined in the same file.