Board Thread:General Mod Discussion/@comment-26029498-20170904175231/@comment-25841881-20170904200239

Yeah, Iguana is an expansion for Tinkers Construct.. Thus the name: Iguana Tinkers Tweaks. I believe it's the thing which allows you to disable vanilla tools' functionality, so people have to use Tinker's Construct tools, and adds the leveling up of tools.