tracker-miner-rss-3 - Used to populate Tracker with RSS feed data.
tracker-miner-rss is not supposed to be run by the user since it is started by its .desktop file when the user logs in. It can also be started manually of course for debugging purposes. You can not run more than one instance of this at the same time.
tracker-miner-rss mines information about RSS feeds only.
You can use tracker-search --feeds to get the latest feed information.