The full GTA V source code has been leaked The leak contains GTA V source code and stuff from Bully 2 and GTA VI Leaked in a discord server by a random British guy in the 360 modding community known to get sued by Rockstar multiple times
"Now i am expecting a open source version of gta to arrive soon on linux natively . Tired of playing supertuxcart."
Here is the source. Another one.
Yeah, the problem with stolen source code is that you can't really use it for much except maybe developing modding tools, and even then you can't say out loud that you used the source and didn't reverse engineer shit