In May, Facebook announced an overhaul of its Trending Topics feature, which it was beginning to roll out to iPhone users. With that update, clicking a topic would bring you to a carousel of publications that had written about that particular subject rather that just one news source. In a statement, Facebook said, "By making it easier to see what other news outlets are saying about each topic, we hope that people will feel more informed about the news in their region." And the update was meant to get around the news "filter bubble" effect wherein feeds are sometimes limited in scope due to having Facebook friends that all have similar interests.
Along with the news source carousel, Trending News also features actual headlines rather than just a topic -- which was hinted at in the May announcement, but not described in detail. With the headlines come a photo, the name of the outlet that published the headline and how many other sources have written on the subject. Each story is also ranked. For example, while writing this, the 17th headline in my Trending News section was this article of ours and the tab noted that 26 other sources had written on the topic.
The revamped Trending section is now available for most US Facebook users on mobile and the direct navigational tab should be coming to Android users sometime soon.