code: public static void pruneDenseTableColumnsV3(List<RawColumn> columns) {
      ListIterator<RawColumn> iterator = columns.listIterator();
      while (iterator.hasNext()) {
        RawColumn column = iterator.next();
        if (column.kind.equals(KIND_REGULAR) && "empty".equals(column.dataType)) {
          iterator.remove();
        }
      }
    }
docs: Helper method to filter columns while parsing a table's metadata.
  
  <p>Upon migration from thrift to CQL, we internally create a surrogate column "value" of type
  EmptyType for dense tables. This column shouldn't be exposed to the user but is currently
  returned by C*.