* New documentation about receiving plain `dict`s as request bodies: [Bodies of arbitrary `dict`s](https://fastapi.tiangolo.com/tutorial/body-nested-models/#bodies-of-arbitrary-dicts).
    * New documentation about returning arbitrary `dict`s in responses: [Response with arbitrary `dict`](https://fastapi.tiangolo.com/tutorial/extra-models/#response-with-arbitrary-dict).
    * **Technical Details**: