Future south end zone expansion
The final planned phase of the stadium's expansion includes the enclosing of the south end zone, completely enclosing the playing field with two levels of seating (not including club seating and luxury boxes). This plan has been part of the University's master plan since at least the early 1990s, as renderings and models of a fully enclosed stadium have existed since that time. The expansion could add approximately 24,000 seats to the existing 4,525 south end zone "temporary" bleachers. The stadium's final seating capacity is expected to be as much as 125,000 when the south end zone is fully enclosed, supplanting The University of Michigan's Michigan Stadium as the largest football stadium in North America and also becoming the second largest stadium in the world.

I think this is clearly about being the biggest.