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="Flashlight-dimmer.png|217" />
  </query-continue>
  <query>
    <pages>
      <page pageid="41" ns="0" title="Backup LED Light" />
      <page pageid="118" ns="0" title="Microprocessor" />
      <page pageid="138" ns="0" title="Depth of field" />
      <page pageid="179" ns="0" title="Chromatic aberration" />
      <page pageid="203" ns="0" title="Different implementations of a simple Collatz iterator and their performance" />
      <page pageid="233" ns="0" title="STM32F103 Microcontroller" />
      <page pageid="250" ns="0" title="STM32F407 Microcontroller" />
      <page pageid="327" ns="0" title="Arty S7" />
    </pages>
  </query>
</api>