To be honest, this might be one they’d be justified in not wanting you to know. Crazy indeed. Chromium-only, I presume.
They do seem to have some strange restrictions on this. E.g. When you evaluate it the function returns undefined but it also outputs the array underneath. You can right click and save it to variable.
I think the point of this so that you cannot assign the output programmatically, there has to be a person who saves it to a variable by right clicking.
I can’t see any reason for preventing assigning the output programmatically.
The reason is absolutely security concerns. You don't want to leak a function that can expose a list of all objects on the JS heap.