You are looking at the HTML representation of the XML format.
HTML is good for debugging, but is unsuitable for application use.
Specify the format parameter to change the output format.
To see the non HTML representation of the XML format, set format=xml.
See the complete documentation, or API help for more information. 
<?xml version="1.0"?>
<api>
  <query>
    <allredirects>
      <r fromid="66" ns="0" title="光交换广域网" />
      <r fromid="89" ns="0" title="数据中心光网络" />
      <r fromid="67" ns="0" title="无状态数据中心网络" />
    </allredirects>
  </query>
</api>