I can't seem to get the Exports Create/Run endpoint working through either the API explorer or actual calls from code. I am adding the following json to the request body:

{
    "export": {
        "context": "people"
    }
}

and adding the list_id to the query string but all I get in response is HTTP 406 (Not acceptable). Am I doing something wrong?

Additionally, the API explorer doesn't allow you to provide a value of the list_id parameter for this endpoint.