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 gatcontinue="作品圖片模版ABA0201B|61" />
  </query-continue>
  <query>
    <pages>
      <page pageid="3" ns="0" title="首頁" />
      <page pageid="15" ns="0" title="新聞中心" />
      <page pageid="22" ns="0" title="藝術家" />
      <page pageid="55" ns="0" title="施志剛 作品圖片" />
      <page pageid="104" ns="0" title="愛藝術 關於我們" />
      <page pageid="134" ns="0" title="關於我們" />
    </pages>
  </query>
</api>