Why is mergesort space complexity O(log(n)) with linked lists?

Question

Mergesort on an array has space complexity of O(n), while mergesort on a linked list has space complexity of O(log(n)), documented here

I believe that I understand the

Answer 1

The mergesort algorithm is recursive, so it requires O(log n) stack space, for both the array and linked list cases. But the array case also allocates an additional O(n) space, which dominates the O(log n) space required for the stack. So the array version is O(n), and the linked list version is O(log n).