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="site" desc="&lt;i&gt;Site&lt;/i&gt;: General utilities needed by the templates and portals of this wiki." />
      <gadget id="collapsibleTables" desc="&amp;lt;gadget-collapsibleTables&amp;gt;" />
      <gadget id="Edittop" desc="&amp;lt;gadget-Edittop&amp;gt;" />
      <gadget id="UTCLiveClock" desc="Gadget-UTCLiveClock" />
      <gadget id="DotsSyntaxHighlighter" desc="&amp;lt;gadget-DotsSyntaxHighlighter&amp;gt;" />
      <gadget id="Edittools" desc="&amp;lt;gadget-Edittools&amp;gt;" />
      <gadget id="HotCat" desc="&lt;a href=&quot;/index.php?title=W:WP:HOTCAT&quot; title=&quot;W:WP:HOTCAT&quot;&gt;HotCat&lt;/a&gt;, easily add / remove / change a category on a page, with name suggestion &lt;small&gt;&amp;#91;&lt;a href=&quot;/index.php?title=File:HotCat.png&amp;amp;action=edit&amp;amp;redlink=1&quot; class=&quot;new&quot; title=&quot;File:HotCat.png (page does not exist)&quot;&gt;example&lt;/a&gt;]&lt;/small&gt;" />
      <gadget id="TabOverride" desc="TabOverride, allows to input tab characters on the editing area by pressing the tab key on the keyboard" />
      <gadget id="WmfProjectStatusHelper" desc="&amp;lt;gadget-WmfProjectStatusHelper&amp;gt;" />
      <gadget id="oldeditor" desc="&amp;lt;gadget-oldeditor&amp;gt;" />
      <gadget id="templatedata" desc="&amp;lt;gadget-templatedata&amp;gt;" />
      <gadget id="workinprogress" desc="&amp;lt;gadget-workinprogress&amp;gt;" />
      <gadget id="CleanDeleteReasons" desc="Gadget-CleanDeleteReasons" />
      <gadget id="blocktab" desc="&amp;lt;gadget-blocktab&amp;gt;" />
      <gadget id="botRollback" desc="&amp;lt;gadget-botRollback&amp;gt;" />
    </gadgets>
  </query>
</api>