That is just an efficient way to store the original object and linked list of diffs to get to the current object (assuming accessing the current object is more

That is just an efficient way to store the original object and linked list of diffs to get to the current object (assuming accessing the current object is more popular). Note that if you store the original and the diffs, those things are all immutable. Indeed, that is how git works in general – recording changes as immutable commits, and having one or more heads which point to the new immutable commit.