Yeah, I also got suspicious and checked it with Pangram. Sadly 100% AI. Perhaps it still has good points, but my heart drops whenever I sniff the AI prose. I can just query Claude or ChatGPT myself, you know?
It also seems quite plausible that it can be made to work by training on a lot of model output. Most of us already have become very sensitive to the various idiosyncrasies of model writing, after all. They have a very distinctive style.