Supporting content-negotiation (return based on content-type)

Any idea how to add content-negotiation to an endpoint, in a way similar to what is described here for flask-restful:
https://flask-restful.readthedocs.io/en/latest/extending.html#content-negotiation

(also: is the project still being maintained? No update in a while…)

No files, tests, or entry points are named in the issue. Start by reading the linked Flask-RESTful content-negotiation documentation and inspecting how flask-smorest currently handles endpoint responses; done would require an agreed design and tests covering the supported content types.

Written by the indexing model from the issue text.