Depends on what you consider big. The leak is on several websites and includes a near finished version of the game, the Version 43 beta as shown by Sixtyfour's Youtube video posted by Jay Doomed, and the entire game's source code.
Additionally, it contains a few other things, a lot of uncompressed audio, a lot of unused audio, a compressed archive of game assets, a beta music track, and a few "Project Reality" rom demos, which was the development name of the N64.
So, the leak and what it contains is fairly big!
Now, do you mean big as in, did someone do anything? Well, that depends. I think the source code would be fun to learn from, but it'd be illegal to make a game from, and the Turok remasters already exist. The audio might be less controversial, but Darren Mitchell does not want his music re-uploaded or re-used, and I respect that. As for the sound effects, I guess that depends really, a lot of them are exactly the same ones featured in the game, and I think there is no real moral issue in taking uncompressed assets to replace compressed ones. Doesn't mean its legal though.
Finally, this leaves us with the graphics and levels. They're contained in a compressed custom format, much like the one used by the PC version but different. You're never going to be able to access that unless someone cracks it, and I don't think anyone who is able, is willing to. You could try to extract the textures through emulator plugins though.
So, I apologize for this long post, but I just wanted to explain it.
