No, it's not a mod, it's update 0.4.2, which, as far as I understand, lets you create or download custom maps. Honestly, it's a decent update. However, I've noticed two bugs in this map: the window livery looks dark, and the rims do too. What do I mean by this?
Well, let's look at my ZL1.
This is how it should look.
but on the Hangout map, it looks like this.
Anyway, I'd better shut up and enjoy this update.