If you capture any screenshots or video of Child of Light on the PlayStation 4 using the tools provided by Sony, rather than an external capture card, you'll see a Ubisoft logo in the corner.
As Polygon noted yesterday, this is apparently the first game to do so. We verified that the watermark appears in both videos and screenshots on PlayStation 4, though it doesn't appear in videos captured on Xbox One, suggesting this particular functionality may not be available to developers on Microsoft's system.
Interestingly, other Ubisoft titles, even ones released around the same time like Trials Fusion, don't show similar behavior.
The decision to include this is hard to understand. Child of Light is a beautiful game, and visually distinctive. Slapping a logo on every screenshot hurts the look of the screenshot (even if only a bit) and makes the company look unnecessarily possessive.
With that said, I can see some useful applications of the watermarking option. Layering the name of the game over the screenshot could help potential customers track down a particularly good-looking game. There could even be options for what information you'd like to include in the watermark – your PSN id and gamerpic, current information about the game that isn't normally on-screen.
I hope, though, that this particular use of watermarking doesn't become standard. There are lots of gorgeous games coming out, and we don't need them all dotted with unnecessary logos like this.