If you're talking about the recipes, it's open source in that it's public domain. Or it's not open source, because it can't be copyrighted and therefore all the frameworks that allow for open source don't apply. [1]

This is actually _really, really interesting_ and could spur some really great discussion, so I was ready to check out the HN comments only to find... griping about recipe sites. Ctrl+F 'Open Source' to find this comment. Man, HN sucks.

[1] https://www.copyright.gov/help/faq/faq-protect.html#:~:text=...

Source here: https://github.com/locua/oscooking