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-continue>
    <allredirects arcontinue="MindManager/简单教程" />
  </query-continue>
  <query>
    <allredirects>
      <r ns="0" title="CSS" />
      <r ns="0" title="CSS技术文章" />
      <r ns="0" title="CSS选择符" />
      <r ns="0" title="Discuz!X/微商店/数据库字典/pre plugin qq send log" />
      <r ns="0" title="Discuz!X/微商店/数据库字典/pre plugin qq send pool" />
      <r ns="0" title="Discuz!X/数据库字典" />
      <r ns="0" title="Google Chrome" />
      <r ns="0" title="IE6下PNG-24位图片问题集合" />
      <r ns="0" title="ImageMagick 在windows下的安装" />
      <r ns="0" title="MindManager" />
    </allredirects>
  </query>
</api>