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>
    <allfileusages gafcontinue="Basketball.png|3765" />
  </query-continue>
  <query>
    <pages>
      <page pageid="255" ns="0" title="籃球" />
      <page pageid="308" ns="0" title="CBA" />
      <page pageid="460" ns="10" title="模板:協助" />
      <page pageid="466" ns="0" title="NBA勞資爭議停賽事件(2011)" />
      <page pageid="502" ns="0" title="洪氏兄弟" />
      <page pageid="544" ns="10" title="模板:多重含意" />
      <page pageid="945" ns="0" title="周俊三" />
      <page pageid="1056" ns="0" title="Kevin Johnson" />
      <page pageid="2055" ns="0" title="零秒出手" />
      <page pageid="2078" ns="0" title="灌籃大賽" />
    </pages>
  </query>
</api>