the tome verses point to locations of concentric circles hidden around the world. This was apparently part of a planned puzzle, but it was supposedly abandoned.
As for no hint,
here's a post by the person who was the first outside of the development team to unlock it, the person that got the correct solution from a friend "on high," someone who worked on the game. Also note the careful wording of "in-game materials," which lead myself and others to expect a surprise in the soundtrack. Which people
are finding things in it, like intentionally-hidden images, but most people are burned out on the game now, especially after it took such an effort to beat a puzzle that had a completely different scope from the rest of the game.