Effective with Firefox 64, which is the current version as of December 28, 2018, the Firefox browser no longer supports RSS feed discovery or preview. Chrome killed that functionality a while ago. Less than .1% of users used the RSS functionality of Firefox so I guess I can't really blame the developers for killing support.
I think RSS is one of the most under appreciated technologies spawned by the web. In a better world, we'd all be keeping in touch via open technologies like RSS, and not be trapped in walled gardens like Twitter and Facebook. There is a lot of interesting early stage work on open alternatives to Facebook, Twitter, etc. Mastodon as a Twitter alternative is probably the most mature, and the only one that I'm using regularly at the moment. However in 2019 I intend to explore this space further.
This is entry #28 in my attempt at 31 days of blogging for December 2018. I've haven't posted here daily since about 2007, so this should be interesting.