anchor.diff:  == OpenAPI Endpoint
   
   === Overview
  -A fully processed and valid OpenAPI document must be available at the root
  +A fully processed OpenAPI document must be available at the root
   URL `/openapi`, as a `HTTP GET` operation.
   
   For example, `GET http://myHost:myPort/openapi`.
  
positive.code: endpoint.
  
  === Content format
  The default format of the `/openapi` endpoint is `YAML`.
  
  Vendors must also support the `JSON` format if the request contains an `Accept`
  header with a value of `application/json`, in which case the response must contain
  a `Content-Type` header with value of `application/json`.
  
  === Query parameters
  No query parameters are required for the `/openapi` endpoint.  However, one
  
negative.code:     requestBody:
        description: Created user object
        content:
          '*/*':
            schema:
              $ref: '#/components/schemas/User'
              required: true
      responses:
        default:
          description: no description
  