Just looks like the background without any of the characters on it. Doesn’t take long to Photoshop one of those yourself, and OWI will of course have a full collection of the originals.
What’s wrong with that? There are order bombs there in the final game as well. These ones are just higher resolution, because it’s one of those HR screenshots OWI have come up with. There are several. The same applies to this one:
I object to these kinds of screenshots of unfinished versions of games being referred to as ‘mysteries’, but it seems to be the norm. Unless they have an unfamiliar location or gameplay object (e.g. the Elum trap), it’s safe to say that changes are done because they make the gameplay work better, or the visuals look a little nicer.