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="C11|42" />
  </query-continue>
  <query>
    <pages>
      <page pageid="4" ns="0" title="C言語解説" />
      <page pageid="5" ns="10" title="テンプレート:type" />
      <page pageid="6" ns="0" title="bool" />
      <page pageid="11" ns="0" title="quick exitによるプログラムの終了処理" />
      <page pageid="15" ns="10" title="テンプレート:iso" />
      <page pageid="16" ns="0" title="Generic" />
      <page pageid="17" ns="0" title="inline" />
      <page pageid="18" ns="0" title="Noreturn" />
      <page pageid="42" ns="0" title="C99" />
    </pages>
  </query>
</api>