Anyone could implement this. The User-Agent of the feed request should include a subscriber count for each service that is downloading your feed to provide to

Anyone could implement this. The User-Agent of the feed request should include a subscriber count for each service that is downloading your feed to provide to its users. Examples: https://www.jefftk.com/p/looking-at-rss-user-agents https://www.jefftk.com/p/looking-at-rss-user-agents