It's GM-less. I use the term Collaborative because the power is shared and GM is a jargon term that if you don't know what gaming is become a barrier. Not a huge one per say but still one that we can update our terminology to help.
Makes sense & appreciate the explanation- I've also seen these labels/terms:
I'm definitely interested now that I know for sure that it will fit within my collection; be ordering it soon. 👍
Happy to help make things clear for you! ^_^