You are looking at the HTML representation of the XML format.
HTML is good for debugging, but probably is not suitable for your application.
See complete documentation, or API help for more information. 
<?xml version="1.0"?>
<api>
  <query>
    <namespaces>
      <ns id="-2" case="first-letter" canonical="Media" xml:space="preserve">媒体</ns>
      <ns id="-1" case="first-letter" canonical="Special" xml:space="preserve">特殊</ns>
      <ns id="0" case="first-letter" content="" xml:space="preserve" />
      <ns id="1" case="first-letter" subpages="" canonical="Talk" xml:space="preserve">讨论</ns>
      <ns id="2" case="first-letter" subpages="" canonical="User" xml:space="preserve">用户</ns>
      <ns id="3" case="first-letter" subpages="" canonical="User talk" xml:space="preserve">用户讨论</ns>
      <ns id="4" case="first-letter" canonical="Project" xml:space="preserve">美国主机知识库</ns>
      <ns id="5" case="first-letter" subpages="" canonical="Project talk" xml:space="preserve">美国主机知识库讨论</ns>
      <ns id="6" case="first-letter" canonical="File" xml:space="preserve">文件</ns>
      <ns id="7" case="first-letter" subpages="" canonical="File talk" xml:space="preserve">文件讨论</ns>
      <ns id="8" case="first-letter" subpages="" canonical="MediaWiki" xml:space="preserve">MediaWiki</ns>
      <ns id="9" case="first-letter" subpages="" canonical="MediaWiki talk" xml:space="preserve">MediaWiki讨论</ns>
      <ns id="10" case="first-letter" canonical="Template" xml:space="preserve">模板</ns>
      <ns id="11" case="first-letter" subpages="" canonical="Template talk" xml:space="preserve">模板讨论</ns>
      <ns id="12" case="first-letter" canonical="Help" xml:space="preserve">帮助</ns>
      <ns id="13" case="first-letter" subpages="" canonical="Help talk" xml:space="preserve">帮助讨论</ns>
      <ns id="14" case="first-letter" canonical="Category" xml:space="preserve">分类</ns>
      <ns id="15" case="first-letter" subpages="" canonical="Category talk" xml:space="preserve">分类讨论</ns>
    </namespaces>
  </query>
</api>