UMIIS

This small modification for Fabric solves a common problem with inventory management in singleplayer games.

With UMIIS, you can use your multiplayer inventory even in singleplayer mode. No more need to transfer items to chests or copy NBT data to the level.dat file - the mod makes this process automatic and seamless for the player.

An interesting side effect is that when joining a singleplayer world with different accounts, separate inventories will be preserved for each account. This opens up additional opportunities for organizing shared use of one world by different players without mixing their personal belongings.