Not to wreck your theory of anything but...
You know what else is redacted? Everything else that has yet to be confirmed, including the 10th gameworld and what the area behind the tower is for.
Do you know what else is a thing? Everything else that's in the game.
Do you know what else is a map? The Plaza, All of the Condos, All of the Gameworld Maps
No idea what this has to do with anything.
Guess what else has blockout and artwork on it? Literally every single thing in the game.
And, Solar is a map, which means that Project 39 must also be a map! And do you know what I said was a map earlier? The Plaza, The Condos, the Gameworld maps. Johanna is doing the art for Solar, btw, so he's not even connected to Solar.
Point is, Project 39 could literally be anything.