If looking to use Punchh's Atom XMLs for your own RSS Feed/Aggregator, in the Punchh Platform navigate to Feedback>Feedback>Scroll all the way down to the bottom of the page
Here you will find three links:
Choose the appropriate link and Right Click>Copy Link Address and paste this in your Aggregator. This should the actual XML file be needed, you may simply go to one of the above links and you'll be present with the XML coding.