An Atom feed is another kind of web feed that you can use on your site. This is newer than RSS, and is also XML-based.
Here is an example of a Merge Template one might use to generate an Atom feed.
<?output "../atom.xml"?>
<?xml version="1.0" encoding="utf-8"?>
<feed xmlns="http://www.w3.org/2005/Atom">
<title>Adventures with Notenik</title>
<subtitle>The Latest Adventures with the Notenik Mac App</subtitle>
<link href="https://notenik.app/atom.xml" type="application/atom+xml" rel="self" />
<link href="https://notenik.app/" type="text/html" rel="alternate" />
<updated>=$today&yyyy-MM-dd$=T09:00:00Z</updated>
<rights>Copyright © =$today&yyyy$=, Herb Bowie</rights>
<author>
<name>Herb Bowie and the Notenik Community</name>
</author>
<id>https://hbowie.net/atom.xml</id>
<?nextrec?>
<entry>
<title>=$title&x$=</title>
<link rel="related" type="text/html" href="https://notenik.app/adventures/=$date&yyyy-MM-dd$=-=$title&f$=.html"/>
<id>https://notenik.app/adventures/=$date&yyyy-MM-dd$=-=$title&f$=.html</id>
<published>=$date&yyyy-MM-dd$=T09:00:00Z</published>
<updated>=$datemodified&yyyy-MM-ddTHH:mm:ssz$=</updated>
<author>
<name>=$author$=</name>
</author>
<summary>
=$teaser&xo-$=
</summary>
<content type="html">
<![CDATA[
=$body&xo$=
]]>
</content>
</entry>
<?loop?>
</feed>
Notice the use of the XML - X variable modifier in several places to make sure that your variable values are suitably encoded for use within XML.
One would then want to include a line such as the following within the head section of the HTML pages on your site.
<link rel="alternate" type="application/atom+xml" title="Atom feed for Adventures with Notenik" href="atom.xml" />