firebase-ios-sdk 6.29 posted a deprecation warning for setScreenClass and added two features, from their changelog:
Analytics
Added support for manually logging screen views with logEvent(_:parameters:). The setScreenName(_:screenClass:) API will be deprecated and removed in a future major release.
Added setDefaultEventParameters API to support setting parameters that will be logged on all events.
[SKAdNetwork registerAppForAdNetworkAttribution] is now automatically called on first open by default. To opt-out of this default behavior, add the key GOOGLE_ANALYTICS_REGISTRATION_WITH_AD_NETWORK_ENABLED with Boolean value NO to your app’s Info.plist file.