As the title says, this mod allows you to access the Bundles like how you can do in the newer snapshots.
In case you don't know, Bundle is an item that allows you to store as many item types as you want in a single inventory slot. This doesn't increase the capacity, however. It can store up to 64 items. Items with smaller maximum stack size will cost more slots in a Bundle to store, Ender Pearls, for example, will take 4(64 / 16) slots to store a single item.
This mod almost do that perfectly, not gonna lie. You can find it in your creative inventory, crafting tables. If it isn't perfect, just tell me how and we can get a step closer to it! Also, this mod is completely optional on either client or server!