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>
    <revisions rvcontinue="840" />
  </query-continue>
  <query>
    <pages>
      <page pageid="1" ns="0" title="Main Page">
        <revisions>
          <rev user="Dez" timestamp="2016-10-19T17:57:24Z" comment="changed forum link from lfa to steam, where it is active" />
          <rev user="Hexzyle" timestamp="2015-09-03T12:27:16Z" comment="Added changelog link to current version number" />
          <rev user="Hexzyle" timestamp="2015-06-23T17:45:17Z" comment="Added hidden links to front page" />
          <rev user="Hexzyle" timestamp="2015-06-23T16:18:35Z" comment="link to [[OBEY]] page on the mainpage banner" />
          <rev user="Hexzyle" timestamp="2015-06-23T07:15:49Z" comment="Updated power plant icon" />
        </revisions>
      </page>
    </pages>
  </query>
</api>