Pesky Pirates (Anti-Piracy)

Installed on the client, the mod is meant to keep unlicensed copies of the game from getting past a server that a modpack owner has set up. The author describes it as a way to deal with pirate players who try to join a modded server and complain about being rejected for piracy. Pesky Pirates runs only on the client, so a server that wants the check depends on the mod being present on the player's side. The mod is published for Forge only, across two game versions, 1.16.5 and 1.20.1, with 1.1 for 1.20.1 as the latest file. It is released under the MIT License and is open source.