Is there an interface specification of the device provisioning API (which is implemented by the Azure IoT C SDK provisioning_client) available and if yes where can I find it?
I would be interested in the URI, required payload and the json response for the MQTT protocol.
You can reference SDK API Reference Documentation.
And there are REST APIs for Azure IoT DPS, for example, Create or update a device enrollment record:
HTTP request: PUT https://localhost/enrollments/{id}?api-version=2018-04-01
Request Body:
Responses: