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>
    <pages>
      <page pageid="1" ns="0" title="首頁" />
      <page pageid="5" ns="0" title="慎芝" />
      <page pageid="6" ns="0" title="跳舞時代" />
      <page pageid="68" ns="0" title="金曲獎" />
      <page pageid="215" ns="10" title="模板:公告" />
      <page pageid="348" ns="0" title="尋人啟事" />
      <page pageid="373" ns="1" title="討論:在這個分類建新頁面" />
    </pages>
  </query>
</api>