Facebook is testing out a new way to highlight Reactions to your Facebook posts, with a new notification format within your Notifications listing that would display a small tile of the post, with respective Reactions overlaid.
As you can see in this example, spotted by Twitter user @Andresfvasquezh (and shared by Matt Navarra), the new listing would sit in your Notifications listing, but would more specifically highlight individual post Reactions in a more visual format.
That could help spur engagement and response - for one, the more visual notifiers stand out, though you would expect the effect of such would diminish over time. But they might also show a Reaction you weren't expecting, or signify posts that are seeing a lot of response.
It would be a small addition, in relative terms, but you can imagine it having the desired effect - while for brands, it could help to highlight key posts that are sparking emotional response, and get you responding faster to maximize that engagement.
There's no word from Facebook on an official, full roll-out at this stage.