#RSS, as a format, specified here: https://cyber.harvard.edu/rss/rss.html
Feels exceptionally loose and string-based compared to #Atom and #JSONFeed.
Given many of us call Atom feeds RSS, I'm debating on long-term support in this library. As in 1.0 has it - 2.0 doesn't - and there won't be a lot of releases between 1.0 and 2.0.
RSS is the oldest of the 3 and I can't find any organization that's taken ownership of it for further development. Atom is at still part of the w3c. And JSON Feed is just starting.