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="BouhaKS.gif|348" />
  </query-continue>
  <query>
    <pages>
      <page pageid="106" ns="0" title="人工衛星打ち上げ" />
      <page pageid="118" ns="0" title="防衛衛星(R.A.)" />
      <page pageid="161" ns="0" title="Hakoniwa R.A.の人工衛星" />
      <page pageid="515" ns="0" title="防衛衛星(S.E)" />
      <page pageid="565" ns="0" title="銀行" />
      <page pageid="643" ns="0" title="未開の空間" />
      <page pageid="823" ns="0" title="大都市" />
      <page pageid="825" ns="0" title="バトルフィールド" />
      <page pageid="836" ns="0" title="プレゼント" />
    </pages>
  </query>
</api>