Does a Forge version of this mod exist? yes, forge implementations do exist (Mohist), but are unrepresentative of the fabric's requirements.
Does a Fabric version of this mod exist for an older MC version? yes?
Some partial implementations do exist:
CraftFabric https://github.com/tr7zw/CraftFabric (Works on integrated server, possibly with most potential due to visible results, still a ways to go).
Description
An implementation of Bukkit api on fabric.
Details