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="Boot:mbm-90.72.idb.gz|7" />
  </query-continue>
  <query>
    <pages>
      <page pageid="103" ns="0" title="Infineon BGA735L16" />
      <page pageid="109" ns="0" title="Broadcomm BCM4750" />
      <page pageid="342" ns="0" title="Texas Instruments BQ27505" />
      <page pageid="1" ns="0" title="Main Page" />
      <page pageid="7" ns="0" title="Booting chain" />
      <page pageid="352" ns="0" title="Broadcom BCM4325" />
    </pages>
  </query>
</api>