What is this strange image on a Nexus 5x?

[Android Central Question]

There is a strange little image that appears on every screen on my wife's 5x. It just recently started appearing. Doesn't do anything other than annoying my wife. It's in the upper left corner on every function. Never goes away. Anybody have any ideas?

 

[Mythguide]

I would upload a screen shot of the image, but I don't see where to do it.