RSS would be a good query result format to add, so that wiki content can more easily be syndicated elsewhere.
MediaWiki has built-in renderers for Atom and RSS, so both can be supported.
The query options should be along the lines of:
{{#cargo_query: tables = posts
| fields = _pageName, publication_date, description, author
| format = feed
| feed type = rss
| feed title = News From Nowhere
| feed description = Lorem ipsum.
| link text = Subscribe to news
}}It'll use the first date field found for the publication date. The title should be _pageName or a field with alias title.