Interesting response on reddit:
I'm not saying this is fake, I'm saying this is a placeholder for the actual release.
Ravnica. City of guilds. A plane whose main planet is covered in a large city, also referred to as Ravnica.
A setting where the city is the entire reason for going there. A place that isn't Faerun. A place where the inhabitants have an entirely different way of life than that in the Realms. A place where you could meet anybody, make any deal, where travelers from across the planes meet.
Does this sound familiar?
Ladies and gentlemen, you're looking at the placeholder for Sigil.