RSS
RSS 2.0 Specification (version 2.0.11)
RSS Autodiscovery
https://readkit.app/
W3C Feed Validation Service, for Atom and RSS
/rss
や
/feed
を叩いてみると見つかることも、、、！
reader
Readwise reader
My favorite
Feeder – RSS Feed Reader
Reeder 5
Feedbin
inoreader
ReadKit - Have all your reading in one place