Minecraft wiki entry for Loot_table, associated text:  LootTable: Loot table to be used to fill the container when it is next opened, or the items are otherwise interacted with. When the container is a chest that is part of a double chest, only the half corresponding to the tagged single-chest is affected.
 LootTableSeed: Seed for generating the loot table. Works similarly to the seeds for worlds. 0 or omitted uses a random seed.