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>
    <gadgets>
      <gadget id="HotCat" desc="&lt;i&gt;HotCat&lt;/i&gt;: easily add / remove / change a category on a page, with name suggestions &lt;small&gt;[&lt;a rel=&quot;nofollow&quot; class=&quot;external text&quot; href=&quot;http://commons.wikimedia.org/wiki/Help:Gadget-HotCat&quot;&gt;documentation&lt;/a&gt;]&lt;/small&gt;" />
      <gadget id="Reader" desc="&lt;i&gt;Reader&lt;/i&gt;: a read-mostly display, especially suited for narrow phone/tablet displays (requires &lt;b&gt;Vector&lt;/b&gt; skin) &lt;a href=&quot;/MediaWiki:Reader&quot; title=&quot;MediaWiki:Reader&quot;&gt;Configure activation width&lt;/a&gt;" />
      <gadget id="Author" desc="&lt;i&gt;Author&lt;/i&gt;: enable convenience features for wiki authoring" />
      <gadget id="Mailable" desc="Add a mail icon to user pages of people you can email through the wiki" />
      <gadget id="mySandbox" desc="Add a &quot;Sandbox&quot; link to the personal toolbar area." />
      <gadget id="Links" desc="Add a &quot;Links&quot; link to the Toolbox providing links to current revision or a shorter URL" />
      <gadget id="Subpages" desc="Add a &quot;Subpages&quot; link to the Toolbox" />
      <gadget id="CollabOERate" desc="&lt;i&gt;CollabOERate&lt;/i&gt;: enable live editing and navigation collaboration (&lt;i&gt;highly experimental&lt;/i&gt;, &lt;i&gt;&lt;b&gt;requires modern browser&lt;/b&gt;&lt;/i&gt;)" />
    </gadgets>
  </query>
</api>