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>
    <allredirects garcontinue="BB:ステージ４（１Ｃ４）|2188" />
  </query-continue>
  <query>
    <pages>
      <page pageid="1888" ns="0" title="QuestBB:Magnitude of Metal" />
      <page pageid="1963" ns="0" title="BB:Seat of The Heart (Offline Verison)" />
      <page pageid="2164" ns="0" title="BB:Maximum Attack 2" />
      <page pageid="2168" ns="0" title="BB:AOL CUP -Maximum Attack-" />
      <page pageid="2184" ns="0" title="BB:ステージ１" />
      <page pageid="2185" ns="0" title="BB:ステージ１（１ｃ１）" />
      <page pageid="2186" ns="0" title="BB:ステージ２" />
      <page pageid="2187" ns="0" title="BB:ステージ３" />
      <page pageid="2294" ns="0" title="BB:Central Dome Fire Swirl (Online version) (V2)" />
      <page pageid="2296" ns="0" title="BB:Seat of The Heart (Offline Version)" />
    </pages>
  </query>
</api>