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="Barcelona_Cavalry_Regimental_Standard.jpg" />
  </query-continue>
  <query>
    <pages>
      <page pageid="2987" ns="6" title="File:Baaden Infantry Grenadier Mitre Cap.jpg" />
      <page pageid="2986" ns="6" title="File:Baaden Infantry Uniform Plate.jpg" />
      <page pageid="424" ns="6" title="File:Baden-Baden Infantry Uniform Plate 1762.jpg" />
      <page pageid="433" ns="6" title="File:Baden-Durlach Infantry Private.jpg" />
      <page pageid="434" ns="6" title="File:Baden-Durlach Infantry Uniform Plate 1762.jpg" />
      <page pageid="1264" ns="6" title="File:Baguettes Punishment.jpg" />
      <page pageid="654" ns="6" title="File:Banal-Grenzinfanterieregiment nr. 1 Uniform Plate.jpg" />
      <page pageid="656" ns="6" title="File:Banal-Grenzinfanterieregiment nr. 2 Uniform Plate.jpg" />
      <page pageid="683" ns="6" title="File:Banater Grenz-Hussars Uniform Plate 1762.jpg" />
      <page pageid="619" ns="6" title="File:Baranyay Hussars Uniform Plate 1757.jpg" />
    </pages>
  </query>
</api>