If you want to add a new SlotFill component, check the [Checkout - Slot Fill document](../../../../packages/checkout/slot/README.md). To read more about Slot and Fill, check the [Slot and Fill document](./slot-fills.md).
**Note About Naming:** Slots that are prefixed with `Experimental` are experimental and subject to change or remove. Once they graduate from the experimental stage, the naming would change and the `Experimental` prefix would be dropped. Check the [Feature Gating document](../../../internal-developers/blocks/feature-flags-and-experimental-interfaces.md) from more information.
![Example of ExperimentalOrderMeta in the Cart block](https://user-images.githubusercontent.com/1628454/154517779-117bb4e4-568e-413c-904c-855fc3450dfa.png)
![Example of ExperimentalOrderMeta in the Checkout block](https://user-images.githubusercontent.com/1628454/154697224-de245182-6783-4914-81ba-1dbcf77292eb.png)
-`cart`: `wc/store/cart` data but in `camelCase` instead of `snake_case`. [Object breakdown.](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/c00da597efe4c16fcf5481c213d8052ec5df3766/assets/js/type-defs/cart.ts#L172-L188)
-`extensions`: external data registered by third-party developers using `ExtendSchema`. If you used `ExtendSchema` on `wc/store/cart` you would find your data under your namespace here.
![Example of ExperimentalOrderShippingPackages in the Cart block](https://user-images.githubusercontent.com/6165348/118399054-2b4dec80-b653-11eb-94a0-989e2e6e362a.png)
![Example of ExperimentalOrderShippingPackages in the Checkout block](https://user-images.githubusercontent.com/6165348/118399133-90094700-b653-11eb-8ff0-c917947c199f.png)
-`collapsible`: `Boolean|undefined` If a shipping package panel should be collapsible or not, this is false in Checkout and undefined in Cart.
-`collapse`: `Boolean` If a panel should be collapsed by default, this is true if if panels are collapsible.
-`showItems`: `Boolean|undefined` If we should show the content of each package, this is undefined in Cart and Checkout and is left to the actual package logic to decide.
-`noResultsMessage`: A React element that you can render if there are no shipping options.
-`renderOption`: a render function that takes a rate object and returns a render option.
-`cart`: `wc/store/cart` data but in `camelCase` instead of `snake_case`. [Object breakdown.](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/c00da597efe4c16fcf5481c213d8052ec5df3766/assets/js/type-defs/cart.ts#L172-L188)
-`extensions`: external data registered by third-party developers using `ExtendSchema`, if you used `ExtendSchema` on `wc/store/cart` you would find your data under your namespace here.
-`cart`: `wc/store/cart` data but in `camelCase` instead of `snake_case`. [Object breakdown.](https://github.com/woocommerce/woocommerce-gutenberg-products-block/blob/c00da597efe4c16fcf5481c213d8052ec5df3766/assets/js/type-defs/cart.ts#L172-L188)
-`extensions`: external data registered by third-party developers using `ExtendSchema`, if you used `ExtendSchema` on `wc/store/cart` you would find your data under your namespace here.
🐞 Found a mistake, or have a suggestion? [Leave feedback about this document here.](https://github.com/woocommerce/woocommerce-blocks/issues/new?assignees=&labels=type%3A+documentation&template=--doc-feedback.md&title=Feedback%20on%20./docs/third-party-developers/extensibility/checkout-block/available-slot-fills.md)