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>
    <allpages>
      <p pageid="41" ns="0" title="CSAPP第三章阅读笔记" />
      <p pageid="57" ns="0" title="C 语言再学习" />
      <p pageid="20" ns="0" title="Clojure web开发选型" />
      <p pageid="24" ns="0" title="Clojure并发" />
      <p pageid="53" ns="0" title="Corfu 实现和 phxpaxos 源码阅读心得" />
      <p pageid="39" ns="0" title="Docker学习" />
      <p pageid="56" ns="0" title="Elixir 项目的一些经验教训" />
      <p pageid="13" ns="0" title="Express.js集群" />
      <p pageid="37" ns="0" title="Fail2ban配置" />
      <p pageid="36" ns="0" title="Git Hooks应用" />
    </allpages>
  </query>
  <query-continue>
    <allpages apcontinue="Haproxy日志配置" />
  </query-continue>
</api>