Numerous documents and files have leaked for The Witcher 3 online. The leak is apparently the result of a CD Projekt Red employee's Google Drive being hacked. The hacker then posted the details onto Reddit.
Eurogamer state that CD Projekt Red have confirmed the leak to be true. The hacker posted all sorts of details about the story (including ending spoilers), as well as concept art:
Speaking to Eurogamer, CD Projekt Red's marketing boss Michal Platkow-Gilewski said:
"It has come to our attention that some of the production files for The Witcher 3: Wild Hunt have emerged on the internet.
A portion of the files contains information about the story of the game so we strongly advise against accessing them, as this may heavily impact and spoil your future gaming experience.
We also like to reassure everyone that the disclosure of said documents does not affect the development cycle in any way."