ydb/yt/yql/tests/sql/suites/ytflow/input.txt.attr

{
    "_yql_row_spec" = {
        "Type" = [
            "StructType";
            [
                [
                    "value";
                    [
                        "DataType";
                        "String"
                    ]
                ];
                [
                    "codec";
                    [
                        "DataType";
                        "String"
                    ]
                ];
            ]
        ]
    };
    "dynamic" = %true;
}