This is the data pack which add a item "backpack", the item base is "leather_chestplate", so you can wear it if you want!!!
V6+:you can wear on your backpack in chestplate slot now, you need to download the optifine to show the backpack on your back.
How to craft
Backpack Upgrade
You need to download additional datapack alpha file
V6+: you can upgrade backpack follow below step.
1. Drop backpack item and an emerald block on ground.
2. Make sure there is no other item onGround nearby the backpack and an emerald block.
then the backpack upgrade!!!
V4/V5: You can upgrade your backpack to 18 slots with an emerlard block in smithing table,
How to open backpack(v5+)?
1. Drop backpack item on ground
2. Make sure there is no other item onGround nearby the backpack.
3. Sneak, and backpack item will turn into backpack entity.
4. and right click to open and store items inside it.
How to exit gui
Don't destory the barriel, just press the exit button on the right-bottom corner, and the backpack will transform into item type.
How to install
Release is data pack, you need to download it into world-folder/datapacks/
Beta is resource pack, download it into .minecraft/resourcepacks/
Demo Video (old version)