This mod is abandoned, you should not use this

Removing Minecraft RNG in the most brutal way possible

Patches every call to JavaRandom to be deterministic.

Used as an optional dependency for TASmod and in Tool-Assisted Speedrunning to make the game deterministic.

Can be used to change RNG seeds individually, for scientific purposes.

Commands

/killtherng <RNGName> Read the current RNG seed of that value and how many times it has been called
/killtherng <RNGName> <RNGSeed> Set the seed of that value.
/seedingmode Change how and if the RNG value should change. Can be on every tick and more.

Multiplayer

Does work on multiplayer, however a server side installation is required

Caution!

Some unintended side effects may happen when using this in your world. Use with care and play on a backup!