You still have to pay for it because it costs money to make. But it’s completely open-source beer so you can recreate it yourself if you don’t want to buy it pre-made, or you want to modify the recipe.
I have no idea how to make beer otherwise I’d have a crack at this shitpost myself…
A lot of the craft breweries have published their recipes for years. I’ve done beers from Sierra Nevada, Lagunitas, Tree House and Rogue. There’s a few of the recipes in “Homebrewers Recipe Guide” by Higgins, Kilgore & Hertlein, and some that I’ve just picked up on the brewery websites like the one you link.