EULA

Quote from Mojang

If you've bought the Game, you may play around with it and modify it by adding modifications, tools, or plugins, which we will refer to collectively as "Mods." By "Mods," we mean something original that you or someone else created that doesn't contain a substantial part of our copyrightable code or content. When you combine your Mod with the Minecraft software, we will call that combination a "Modded Version" of the Game. We have the final say on what constitutes a Mod and what doesn't. You may not distribute any Modded Versions of our Game or software, and we’d appreciate it if you didn’t use Mods for griefing. Basically, Mods are okay to distribute; hacked versions or Modded Versions of the Game client or server software are not okay to distribute.

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