Illusion is a rewrite of FibLib. It allows you to lie to clients about BlockStates being sent to clients based off player predicates. Take this example...
> Prevent a player from finding Iron Ore while they are sneaking:
This Illusion will remap Iron Ore to Stone on clients when they are sneaking. Iron Ore will still exist on the server, but any interactions will act as if the player interacted with stone - including block-breaking speed, block drops, and more. Illusion can be used as a common-side library mod to block clients from seeing certain blocks, or as a server-side library to prevent vanilla clients from receiving certain block IDs.
Illusion is available on GitHub for download at https://github.com/Draylar/illusion and is available under the MIT license. Gradle dependencies can be found at https://maven.draylar.dev