Advantage on any saving throw you make to end the grappled condition. To me, this is probably a straight-up error in the Goliath entry. Ending the grappled condition is a check, not a saving throw, in the new rule (which is good for folks with proficiency in athletics or acrobatics). I don't believe that there will be monster stat blacks where you can escape the monster's grapple with a saving throw either. In the appendix, both the Giant Crab and the Constrictor snake grapple, and all it gives is the "escape DC."