tcn.org.preferences.v1alpha1.DialOrder(DialOrder)

Dial order holds either a type enum, or one or more contact field
description fields for custom order.

{
    "custom": {
        "dial_order_fields": [
            {
                "contact_field_description_display_name": "string",
                "contact_field_description_sid": 0
            }
        ]
    }
}