how would I make a mod
is there like a tutorial or something
This game has a built-in support for mods. Now, mods are JSON files that patch game core data with new cards, recipes, etc. See the files at the link above - these are plain text files that contain the recipe you requested. Click on the “manage mods” link at the main menu, then click “load mod” and upload the JSON file. Then click “activate” and “go back to menu”. That’s it, your game will now have cat breeding recipes :)