This is an UnifiedPush Distributor that uses FCM („Firebase Cloud Messaging“ aka „Google Cloud Messaging“). It works out of the box, you don’t need to specify any server.
Anti-Features:
NonFreeComp (the application includes non-free components):
⇒ contains libraries of Google Mobile Services, Google Cloud Messaging, Firebase
NonFreeNet (this application promotes/depends a non-Free network service):
⇒ connects to Google Servers (Firebase/cloud messaging)