Autodiscovery is a useful technique for browsers and software to easily find a website’s RSS feed, regardless of the format, using the link element from HTML and XHTML. The link must be added to the header of each page where the user might want to know that a feed is available, but publishers should include only one autodiscovery link per page, using it to identify the site’s primary feed. This specification also outlines three attributes that describe the link relationship: href, rel, and type, and emphasizes that attributes must be lowercase. This document is available under a Creative Commons Attribution-ShareAlike 2.0 license, and was contributed to by Rogers Cadenhead, James Holderness, and Randy Charles Morin.
https://www.rssboard.org/rss-autodiscovery