That isn't to say any claims that feeds are almost a thing of the past holds any water. There are almost certainly more feeds now than at any point before. The second derivative is probably a flat line, though, which is what I imagine is behind the perception of deathliness. Feed consumption, on the other hand, is almost certainly down—but only if you exclude podcasts.
The first few times it didn't pick up a feed, I would inspect the page source, and sure enough, no `link` tag in the head for the feed (nor references to "rss" or "atom" or "feed" anywhere in the page).
I don't know what stack they use, but I find this particularly common for company blogs.
With RSS you have to make the request periodically to stay up to date, so I'd say you trade some of that temporal tracking for extra geotracking.
It's important to note that Firefox is all but legally owned by Google at this point. It exists on Google's dollar so Google can point at it during anti-trust lawsuits.