Query RSS feed
The Query RSS feed web part can be used to create a feed based on a custom query entered in the web part properties. It uses a built-in query data source as a source of the feed data. It displays a link leading to the feed, which is located at the URL of the page where the web part is placed, with a querystring parameter appended.
The web part belongs to the Syndication module. Full documentation of the module can be found in Kentico CMS Developer's Guide -> Modules -> Syndication.