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>
    <alllinks galcontinue="CAM|17" />
  </query-continue>
  <query>
    <pages>
      <page pageid="5" ns="3000" title="private:用語作成候補" />
      <page pageid="18" ns="0" title="CAM" />
      <page pageid="19" ns="0" title="3D-CAD" />
      <page pageid="22" ns="0" title="NC工作機械" />
      <page pageid="70" ns="0" title="ポストプロセッサ" />
      <page pageid="85" ns="0" title="GPU" />
      <page pageid="178" ns="8" title="MediaWiki:Common.css" />
      <page pageid="214" ns="0" title="美的曲線" />
      <page pageid="215" ns="0" title="メッシュ処理" />
    </pages>
  </query>
</api>