Explain multiple controllers at once(update 2.1)

[JackieMoon1]

Describe the feature

Can someone explain this to me? I saw something experimental was implemented release 2.1 for a second controller, but I haven't been able to get the second controller to work. I've tried games like minecraft and gang beasts but the only button that registers is the xbox button. If anyone knows how to use 2 controllers with one client it would be greatly appreciated if they described how.

Also if someone could, please explain why there are 4 controller slots on greenlight in the 1st place. What is the functionality there?

Describe the use case

Coop from remote locations

Additional information

No response