[pantelisk]

Author here. License is pretty much do whatever you want with it (free as in free information and free beer), I suppose the closest one to that would be MIT, but I don't like its serious legalese tone. I prefer the whimsical "free as in..." phrase

[ranger_danger]

I would say CC0 or just plain "Public Domain" would be even simpler than MIT, since there's no requirement to show the license text to anyone or to have a copyright text.