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="VCAT2_Approve_WorkingVersion_ConfirmApproveDialog.png" />
  </query-continue>
  <query>
    <pages>
      <page pageid="202" ns="6" title="File:Dsc0035.jpeg" />
      <page pageid="630" ns="6" title="File:GoogleSignIn BlockCookies WillNotWork.png" />
      <page pageid="203" ns="6" title="File:Img0159.jpeg" />
      <page pageid="204" ns="6" title="File:Stevepeery.jpeg" />
      <page pageid="29" ns="6" title="File:VCAT2 1IndivStud.png" />
      <page pageid="32" ns="6" title="File:VCAT2 2StudGroups.png" />
      <page pageid="346" ns="6" title="File:VCAT2 A Tab Import.png" />
      <page pageid="7" ns="6" title="File:VCAT2 AllStudents DataEntry.png" />
      <page pageid="336" ns="6" title="File:VCAT2 Approve DraftVersion.png" />
      <page pageid="335" ns="6" title="File:VCAT2 Approve WorkingVersion 1version.png" />
    </pages>
  </query>
</api>