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>
    <alltransclusions atcontinue="中國台商" />
  </query-continue>
  <query>
    <alltransclusions>
      <t ns="10" title="模板:Column1a0" />
      <t ns="10" title="模板:DiamondHouse “豈止於愛”鑽石雞尾酒會" />
      <t ns="10" title="模板:Uneedadvs連鎖加盟廣告" />
      <t ns="10" title="模板:Uneedadv一般廣告" />
      <t ns="10" title="模板:Uneedadv世界文學廣告" />
      <t ns="10" title="模板:Uneedadv專欄廣告" />
      <t ns="10" title="模板:世界文學 上版型A002" />
      <t ns="10" title="模板:世界文學 下版型A002" />
      <t ns="10" title="模板:世界文學 版型A002" />
      <t ns="10" title="模板:中國十二五規劃" />
    </alltransclusions>
  </query>
</api>