Atom is an XML-based document format that is used to describe 'feeds' of related information. A typical use is in a news feed where the information is periodically updated and which users can subscribe to. The Atom format is described in tools.ietf.org/html/rfc4287

The Atom module provides support in reading and creating feeds.

See the RSS module for examples consuming and creating feeds

Namespace
Constants
URI = "http://www.w3.org/2005/Atom"
 

The Atom URI W3C Namespace

XHTML_URI = "http://www.w3.org/1999/xhtml"
 

The XHTML URI W3C Namespace