Are there any open source AI humanizer tools?

Does an open source AI humanizer actually exist, or is this entirely a closed-source commercial space?

Most discussion I’ve found is around commercial SaaS products, and I’m wondering if there’s a GitHub project or similar that implements the same kind of text restructuring without being a paid product. Even something less polished that requires more technical setup would be worth knowing about.

There are a handful of academic and open research projects around adversarial text generation against AI detectors, but they’re typically research code, not polished consumer tools. Expect to need to run them locally with some technical setup.