atomizer

Atomizer makes Atom feeds for your site. All it needs to output an XML
compatible with the Atom Syndication Format is a pair of files containing
the relevant metadata for the site and for its posts.

The standard: <https://en.wikipedia.org/wiki/Atom_(Web_standard)>

For all the details, please do see the README

Open it easily with:
  (find-file-read-only "README.org")   <--- C-x C-e here¹

or from any buffer:
  M-x atomizer-see-readme

or read it online:
  <https://flandrew.srht.site/listful/sw-emacs-atomizer.html>

¹ or the key that ‘eval-last-sexp’ is bound to, if not C-x C-e.