I did a search that returned no results, and clicked on the “Perhaps start a new topic”. It showed this composition at the bottom:
That “category” dropdown doesn’t do anything when you click it.
I filled out the subject and body and tried to create a topic. It doesn’t work, because it doesn’t have a category (because you can’t change the category from empty).
So basically, there’s no way to actually “Perhaps start a new topic” from there.