3.2.5.3.1.2 Response Body
The format of the response body is defined in [RFC8628] section 3.2 (Device Authorization Response).
In addition to the response parameters defined in [RFC8628], the server can also send the following response parameters:
message: OPTIONAL. This parameter specifies a message with the user code and the verification URI that can be displayed to the end user.
verification_url: OPTIONAL. This parameter has the same value as the response parameter verification_uri which is described in [RFC8628] section 3.2 (Device Authorization Response).