RSSAid appRSSAid is Reading tool that is open source under the MIT license. RSSAid is a client app for RSSHub. RSSHub is an open source project to generate RSS links for websites that don't support rss, then you can use the rss link in your own RSS reader to subscribe.
You can deloy the RSSHub service on your own server or use the free service provided by the project author. What RSSAid does is simple: it is just a tool not a RSS reader, you input a link like https://www.reddit.com/r/Fedora/, then RSSAid can generate the RSS link according to RSSHub rules and base url (RSSHub service hostname).