The licenseis a lot better than it was previously. (And by that I mean it’s less worse than a basic MIT-style FOSS license, not that it’s “good”.) Now it does allow derivative works (just not derivative works that remove the “pay FUTO” button, and it doesn’t allow selleing GrayJay or derivative works, and it requires a “prominent” notice if you’ve made changes.)
And the old version had a bit about how FUTO could change the terms at any time for no reason, which basically made it entirely useless.
You can not fork it and retain ownership of the code.
Technically, MIT-style licenses (let alone copy-left licenses) don’t either, I’m pretty sure. Though that’s more true in one sense of the GrayJay Core License than of Open Source licenses.