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="Img-redis.jpg|88" />
  </query-continue>
  <query>
    <pages>
      <page pageid="1" ns="0" title="Main Page" />
      <page pageid="7" ns="0" title="Clear Magento Cache" />
      <page pageid="9" ns="0" title="Disable Magento Modules" />
      <page pageid="11" ns="0" title="Turn on Manual Indexing" />
      <page pageid="21" ns="0" title="Check if Memcached is Running" />
      <page pageid="50" ns="0" title="Crontab Usage" />
      <page pageid="80" ns="0" title="Centos 6" />
      <page pageid="93" ns="0" title="GPG: Encrypt And Decrypt Files With A Password" />
      <page pageid="252" ns="0" title="What is HAProxy" />
    </pages>
  </query>
</api>