In The Scrum Guide the following is written to describe the Sprint Goal.
The selected Product Backlog items deliver one coherent function, which can be the Sprint Goal. The Sprint Goal can be any other coherence that causes the Development Team to work together rather than on separate initiatives.
So it seems that something else then the coherent function provided by "Done" selected Product Backlog items, can by a Sprint Goal.
I don't get that. What does it mean that a Sprint Goal can be any other coherence?