* Add additional `responses` parameter to *path operation decorators* to extend responses in OpenAPI (and API docs).
* It also allows extending existing responses generated from `response_model`, declare other media types (like images), etc.
* The new documentation is here: <a href="https://fastapi.tiangolo.com/tutorial/additional-responses/" target="_blank">Additional Responses</a>.
* `responses` can also be added to `.include_router()`, the updated docs are here: <a href="https://fastapi.tiangolo.com/tutorial/bigger-applications/#add-some-custom-tags-and-responses" target="_blank">Bigger Applications</a>.
* PR <a href="https://github.com/tiangolo/fastapi/pull/97" target="_blank">#97</a> originally initiated by <a href="https://github.com/barsi" target="_blank">barsi</a>.
* Update `scripts/test-cov-html.sh` to allow passing extra parameters like `-vv`, for development.