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>
    <allpages apcontinue="EPICアイコン" />
  </query-continue>
  <query>
    <allpages>
      <p pageid="263" ns="0" title="CA" />
      <p pageid="247" ns="0" title="CAヤード" />
      <p pageid="254" ns="0" title="CB" />
      <p pageid="550" ns="0" title="Deak:ナイトクドゥラク" />
      <p pageid="317" ns="0" title="Deck:オーラでブレイク" />
      <p pageid="258" ns="0" title="Deck:ヒャッハー!〇〇は消毒だー！" />
      <p pageid="260" ns="0" title="Deck:暗黒の領主時代ラッシュ" />
      <p pageid="269" ns="0" title="Deck:紫白 全体除去ビート" />
      <p pageid="268" ns="0" title="Deck:紫速攻 3種のCB デッキ" />
      <p pageid="262" ns="0" title="Deck:進撃の脳筋" />
    </allpages>
  </query>
</api>