OptionalcategoryA kind-level grouping - 'herb', 'runestone', 'potion' - so a recipe can ask for "any
herb" rather than one exact id. Like stackable and weight it describes the item's kind,
so it comes from the game's item definitions on load and is not part of a save.
ReadonlyidOptional ReadonlymodifiersOptional ReadonlyslotOptionalstackableOptionalweight
the kind-level fields a game's own item table supplies, rather than the save file