Update: It seems that this is all related to Facebook's Trending topics. The addition of the News search option enables you to view search results basically in the format that Facebook already shows trending topics when you click on them. You see different types of results like: "In the Story," "Friends and Groups," "Articles," etc.
A Facebook spokesperson tells us, "We’re piloting a new way to discover Trending topics through Facebook Search."
It's a small pilot running on desktop in US English for now. When people who are part of the pilot search for a topic that’s currently trending (either verbatim or with related keywords), they’ll see a link to that Trending topic page at the top of their search results.
Facebook is messing around with its desktop search interface. In one version we're seeing, it has changed the placement of the navigation for different search options on the results page and added a new "News" option.
Here's what the standard Facebook search results page looks like:
Here's the new version I'm currently seeing (with the News option):
The addition of "News" is the only the difference as far as I can tell. I'm a little surprised there's not a Videos option considering the emphasis Facebook has been putting on video all year (including a new News Feed update).
It's unclear if this is a small test or if Facebook intends to push the change to all users. It's most likely just a test for now. We've reached out to the company for comment, and will update accordingly.