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="CMOS_e_OpenCollector_schemi.png" />
  </query-continue>
  <query>
    <pages>
      <page pageid="627" ns="6" title="File:BCP example 01.png" />
      <page pageid="628" ns="6" title="File:BCP example 02.png" />
      <page pageid="629" ns="6" title="File:BCP example 03.png" />
      <page pageid="836" ns="6" title="File:BCP help usage.png" />
      <page pageid="993" ns="6" title="File:CLR Assembly 01.png" />
      <page pageid="994" ns="6" title="File:CLR Assembly 03.png" />
      <page pageid="995" ns="6" title="File:CLR Assembly 04.png" />
      <page pageid="997" ns="6" title="File:CLR Assembly 05.png" />
      <page pageid="996" ns="6" title="File:CLR Assembly 06.png" />
      <page pageid="998" ns="6" title="File:CLR Assembly 07.png" />
    </pages>
  </query>
</api>