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="連立一次方程式|5" />
  </query-continue>
  <query>
    <pages>
      <page pageid="14" ns="0" title="OpenMP並列プログラミング" />
      <page pageid="2" ns="0" title="Windows Tips" />
      <page pageid="10" ns="0" title="プログラミング言語、処理系" />
      <page pageid="1" ns="0" title="メインページ" />
      <page pageid="5" ns="0" title="数値解析" />
    </pages>
  </query>
</api>