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"?>
    <allfileusages gafcontinue="B52_carpet.jpg|100075762" />
      <page pageid="100033326" ns="0" title="B-17 Flying Fortress (bomber)" />
      <page pageid="100033336" ns="1" title="Talk:B-17 Flying Fortress (bomber)" />
      <page pageid="100033352" ns="0" title="B-29 Superfortress (bomber)" />
      <page pageid="100068000" ns="0" title="Doolittle Raid" />
      <page pageid="100075762" ns="0" title="B-52 Superfortress" />
      <page pageid="100080234" ns="0" title="Aircraft carrier" />
      <page pageid="100111085" ns="0" title="B-25 Mitchell" />
      <page pageid="100111090" ns="0" title="B-26 Marauder" />