Originally Posted by Ixal
Much of the 5E rules fall under the SRD, so there would not be much of a problem if they are shown in the game.
But keep in mind, Larian can't simply copy the D&D SRD rules but they need to write their own version of the PHB to account for all the changes they made.
Larian has the license for PHB, if not all of the 5e books. They wouldn't need to limit themselves to the SRD.

And yes you're exactly right. But that makes it even more important that they do write up the rules, so that it's easily apparent what they changed.