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>
    <allpages gapcontinue="名前空間について" />
  </query-continue>
  <query>
    <pages>
      <page pageid="408" ns="0" title="ヘルプ：用語の雛形（協議項目用）" contentmodel="wikitext" pagelanguage="ja" touched="2014-09-09T04:17:21Z" lastrevid="970" counter="10020" length="657" />
      <page pageid="407" ns="0" title="ヘルプ：用語の雛形（固定項目用）" contentmodel="wikitext" pagelanguage="ja" touched="2014-09-09T04:17:21Z" lastrevid="1767" counter="13161" length="1290" />
      <page pageid="1" ns="0" title="メインページ" contentmodel="wikitext" pagelanguage="ja" touched="2014-11-18T04:53:22Z" lastrevid="3089" counter="296328" length="7338" />
      <page pageid="239" ns="0" title="利用者登録について" contentmodel="wikitext" pagelanguage="ja" touched="2014-08-22T10:39:28Z" lastrevid="1349" counter="31796" length="1713" />
    </pages>
  </query>
</api>