There's a nod to a certain man named Bryan, one of the developers at Insomniac, who worked on this game. It's in the Summer Forest hubworld. On the opposite from the Idol Springs portal, there is a wall with a purple crystal on it. Below it is a scribbled text that spells the letters 'B-R-Y-A-N'. There is another place in Summer Forest where you can find this name. In the castle garden area with the Sunny Beach portal, you'll spot the name again, above one of the red buttons.