New Feature?!: "AI Toolkit Training" in trainer options

It's a new thing I noticed and I don't think it was there when I trained a bunch of things a few days ago. I've got no idea what this actually does other than require setting sample prompts for epoch pics (which you should do anyways because the site's "automatic" ones are terrible). It claims to "Train using the AI Toolkit engine, offering improved quality and flexibility.", but I've got no idea what that means. Anyone know?