Used for lists consisting of questions and answers, and can be divided into sections. Every entry in a <qandaset> must contain a question, but answer elements are optional (some questions have no answers), and may be repeated (some questions have more than one answer). Common uses for this element include reader questionnaires and lists of “Frequently Asked Questions” (FAQs).

<qandaset defaultlabel='qanda'>
 <qandaentry>
  <question>
   <para>
    To be, or not to be?
   </para>
  </question>
  <answer>
   <para>
    That is the question.
   </para>
  </answer>
 </qandaentry>
</qandaset>

The defaultlabel attribute identifies the default label that should be used for question and answer elements:

If no value is specified, the implied presentation may be any one of these, as defined by the stylesheet. Note that each question and answer can explicitly define a label, regardless of the default label specified.

See also quandaentry, question, and answer.

http://docbook.org/tdg/en/html/qandaset.html