Sometime people want to use FCM in Android only, and use APNS in iOS. But so tired to apply PushNotifiactionIOS module too. If RN Firebase module support APNSToken property in FCM iOS SDK, many people use APNS token without PushNotifiactionIOS . https://firebase.google.com/docs/reference/ios/firebasemessaging/api/reference/Classes/FIRMessaging?hl=ko#apnstoken

if possible, i want to develop this feature and request PR.