I must admit that I didn’t understand what is this about. I’m not a programmer as well.
But I found something that maybe do what I wanted.
When I’m browsing a site in Firefox in my smartphone that I want to subscribe in tt-rss, I look for the RSS icon on the site, then I click it, and then a window pops up asking me with which program I want to complete the action: Firefox or Tiny Tiny RSS (Andrew Dolgov’s tt-rss client for Android). When I choose the latter, the site is subscribed.