Where the recipe advancements are kept.

Recipe advancements trigger when a player completes certain objectives--in the case of Reg's More Foods, they will trigger when a player picks up or has certain ingredients.
For example, obtaining Cheese for the first time will activate several recipe advancements that are looking for Cheese, and thus give the player multiple recipes that require Cheese.

Some recipe advancements can detect multiple items instead of just one. Thus, they will trigger if one of the ingredients in the list are found.