Level 15 has got nothing in it, but still there is a great chance that you will end up wasting a lot of your time looking for a clue, when it was just infront of you. Well, when you open the link, and download the image to your computer and open it. Its all unavailable.
That’s where the next level is, unavailable. But it doesn’t has an extension, its just unavailable.
Good luck!!!
Nope,by hex viewing this file there is text “Level 16: unavailable” wich leads you to url unavailable,you never have to predict.