Does Xamarin Testcloud show me the result of my app running on real devices or the result of my app running in a simulator/emulator?

So is there a system with thousands and / upon thousands of real devices in the cloud or are there just a bunch of virtual machines running that process the app via an simulator/emulator and return the result?

I know that the websites states that there are real devices, I just want to be sure how it works.

I cannot find a photo of the cloud in google.

thx for clearifaction.