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

Mergesort is a recursive algorithm. Each recursive step puts another frame on the stack. Sorting 64 items will take one more recursive step than 32 items, and it is in fact the size of the stack that is referred to when the space requirement is said to be O(log(n)).