I missed this when it happened. Subscribe to Feed, a macOS Safari extension by @danielpunkass that makes it easy to subscribe to RSS feeds, is now part of @NetNewsWire 5. The Safari extension will work with NetNewsWire and with most other RSS readers on the Mac.
Subscribe to Feed was the inspiration behind Feed Hawk. I am not the original developer of Unread, but I think it is safe to assume that NetNewsWire was a huge inspiration behind Unread and most other RSS readers.