The capacities are 3000 mAh for the smaller S8, and 3500 mAh for the S8+, which jibes with what we've heard before about the battery compartment of Samsung's upcoming flagships, and corroborated by a previous S8+ battery snapshot leak. What else can we glean from these two batteries? Well, the cells are made in Korea, not in China this time, and assembled in Samsung's huge factory in Vietnam, where a number of the US phone versions by Samsung usually come from.
There is another pretty telling detail, though. The WSJ reported not long ago that Samsung is in talks with Murata to become its third battery supplier for the Galaxy S8 batteries, and, sure enough, the battery packs here are marked with "Samsung Japan," so the actual design may be coming from Sony's former battery subsidiary that is in the process of being acquired by Murata.