{
    "description": "Undefined type (deprecated)",
    "bson_type": "0x06",
    "deprecated": true,
    "test_key": "a",
    "valid": [
        {
            "description": "Undefined",
            "bson": "0800000006610000",
            "extjson": "{\"a\" : {\"$undefined\" : true}}"
        }
    ]
}