You start at a 10x10 world border, every unique item that you can collect expands it by 1 block, Can you collect them all? Supports Multiplayer.
This is what you see after you collect 5 unique items, and see the newly expanded border, 1384 Items for 1.21.11.
This is what you see immediately as you join the world with it on.
This shows just how simple it is to utilize the datapack