Microsoft is testing outlining the individual search result snippets within Bing Search. So when you look at a snippet, it has this outline around it, and then when you hover your cursor over it, it highlights more.
Google has done variaitons of this test over the years.
This was spotted by Sachin Patel who shared a bunch of screenshots and videos - here is one of those screenshots from X:
Here is a GIF of it in action:
I am not sure I like it.
Forum discussion at X.
