Ha! It must be a special high thermal dissipation sticker, as the only stuff under that is 5 thermal vias and the revision code.
Checking the other 4D Systems products (I have one of their OLED displays, it doesn’t have such a sticker – looks like it’s a new thing), there’s even stranger places they put them. I can only imagine the date code on it is what’s important.. but doesn’t seem very robust as a ‘warranty void’ type mechanism.