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>
    <recentchanges rccontinue="20170618141220|268" />
  </query-continue>
  <query>
    <recentchanges>
      <rc type="edit" ns="0" title="neovimをMac OS XにHomebrewコマンドでインストールする" pageid="55" revid="279" old_revid="278" rcid="278" timestamp="2017-09-25T14:39:45Z" />
      <rc type="edit" ns="0" title="neovimをMac OS XにHomebrewコマンドでインストールする" pageid="55" revid="278" old_revid="174" rcid="277" timestamp="2017-09-25T14:35:09Z" />
      <rc type="new" ns="0" title="vimで長い行があるファイルの編集が重たくなる現象の対策" pageid="82" revid="277" old_revid="0" rcid="276" timestamp="2017-09-17T09:41:38Z" />
      <rc type="edit" ns="0" title="メインページ" pageid="2" revid="276" old_revid="273" rcid="275" timestamp="2017-09-17T09:31:33Z" />
      <rc type="edit" ns="0" title="vimでファイル全体をソートする方法" pageid="81" revid="275" old_revid="274" rcid="274" timestamp="2017-09-09T14:29:42Z" />
      <rc type="new" ns="0" title="vimでファイル全体をソートする方法" pageid="81" revid="274" old_revid="0" rcid="273" timestamp="2017-09-06T14:04:54Z" />
      <rc type="edit" ns="0" title="メインページ" pageid="2" revid="273" old_revid="271" rcid="272" timestamp="2017-09-06T13:58:07Z" />
      <rc type="edit" ns="0" title="なぜvimを使うのか" pageid="11" revid="272" old_revid="267" rcid="271" timestamp="2017-06-18T14:15:17Z" />
      <rc type="edit" ns="0" title="メインページ" pageid="2" revid="271" old_revid="264" rcid="270" timestamp="2017-06-18T14:14:44Z" />
      <rc type="edit" ns="0" title="vimの設定ファイル" pageid="24" revid="270" old_revid="78" rcid="269" timestamp="2017-06-18T14:12:39Z" />
    </recentchanges>
  </query>
</api>