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="20180421022230|734" />
  </query-continue>
  <query>
    <recentchanges>
      <rc type="edit" ns="0" title="入出力ストリーム" pageid="15" revid="773" old_revid="718" rcid="744" timestamp="2019-08-31T07:03:31Z" />
      <rc type="edit" ns="0" title="newとdelete" pageid="91" revid="772" old_revid="588" rcid="743" timestamp="2018-04-21T13:02:05Z" />
      <rc type="new" ns="0" title="C++はヌルポインタをdeleteしても問題ない" pageid="279" revid="771" old_revid="0" rcid="742" timestamp="2018-04-21T12:51:11Z" />
      <rc type="edit" ns="0" title="C++言語解説" pageid="12" revid="770" old_revid="769" rcid="741" timestamp="2018-04-21T12:34:54Z" />
      <rc type="edit" ns="0" title="C++言語解説" pageid="12" revid="769" old_revid="763" rcid="740" timestamp="2018-04-21T02:46:31Z" />
      <rc type="edit" ns="0" title="nullptr" pageid="178" revid="768" old_revid="766" rcid="739" timestamp="2018-04-21T02:45:44Z" />
      <rc type="edit" ns="0" title="キャスト" pageid="171" revid="767" old_revid="422" rcid="738" timestamp="2018-04-21T02:45:29Z" />
      <rc type="edit" ns="0" title="nullptr" pageid="178" revid="766" old_revid="430" rcid="737" timestamp="2018-04-21T02:45:04Z" />
      <rc type="edit" ns="0" title="メモリの二重解放" pageid="278" revid="765" old_revid="764" rcid="736" timestamp="2018-04-21T02:44:02Z" />
      <rc type="new" ns="0" title="メモリの二重解放" pageid="278" revid="764" old_revid="0" rcid="735" timestamp="2018-04-21T02:42:25Z" />
    </recentchanges>
  </query>
</api>