The CSV format does not contain response metadata and only contains the query results. The response contains a line for each row, where each line contains the row columns separated by a comma. The first line contains the column names if includeColumns is set to true in the submitted request.
The following is an example CSV response to SELECT * FROM DBC.DBCInfo with includeColumns set to true.
InfoKey,InfoData VERSION,15.00.00.01 LANGUAGE SUPPORT MODE,Japanese RELEASE,15.00.00.01