I get several debug messages from Firebase - quite chatty:
2016-10-20 22:18:33.576 Sitch[1190] <Debug> [Firebase/Core][I-COR000019] Clearcut post completed
I don't see any way to quiet them. FIRAnalytics only shows INFO and more severe but Firebase/Core seems to have debug enabled by default?
This is the cocoapods build - from podfile.lock:
FirebaseCore (3.4.3):
GoogleInterchangeUtilities (~> 1.2)
GoogleUtilities (~> 1.2)