Does anyone know what has happened to Kitchenowl?

All I see is a 404 when I go to the Kitchenowl website (https://kitchenowl.org/), docs site (https://docs.kitchenowl.org/) or the author’s Github (https://github.com/TomBursch/kitchenowl/).

I am looking at updating my email stack after a number of years and am wondering what to do for anti-spam. Is Spamassassin still the best option, or is there something better nowadays?