Educational Purposes Only. It's a simple scheme for learning, implementations is not good and most of them not finished yet.
It's a simple local proxy for Minecraft. With local proxy you can attack to connection via Man In The Middle and you can create/delete/change packets. It's a good way for creating hacks for custom minecraft clients.
For example you can create hacks like KillAura, Speed, Fly, ChestStealer, Blink and so on.