The problem is when users want to have the item added to their inventory with cheat giveitemnum. The other problem is that when there is a game update without a devkit update at the same level. You also cannot use cheat giveitemnum for the new items because the master list does not have them in the PrimalGameData of your mod. So modders end up dealing with ******** and moaning by users about not being able to cheat the items in. So the idea to avoid this with ‘AdditionalItemList’ the same as AdditionalStructuresToPlace does. Then the master item list would need to be ignored from the PrimalGameData(whateveryourmodis) file from the mod and the one used is the master item list from PrimalGameData of the latest patch.