The way it works is that you write the definition of the schema using YAML format inside the docstring of each function handling a route.
-And it generates Swagger 2.0 schemas (OpenAPI 2.0).
+And it generates OpenAPI schemas.
That's how it works in Flask, Starlette, Responder, etc.
It's a Flask plug-in, that ties together Webargs, Marshmallow and APISpec.
-It uses the information from Webargs and Marshmallow to automatically generate Swagger 2.0 schemas, using APISpec.
+It uses the information from Webargs and Marshmallow to automatically generate OpenAPI schemas, using APISpec.
It's a great tool, very under-rated. It should be way more popular than many Flask plug-ins out there. It might be due to its documentation being too concise and abstract.