9.4.1 is a Swift Package Manager only tag, which is equivalent to CocoaPods 9.4.0 tag. The 9.4.0 tag for Swift Package Manager was incorrectly placed on the 9.3.0 tag.
The Firebase Apple SDK (9.4.1) is now available. For more details, see
the Firebase Apple SDK release notes.
To install this SDK, see Add Firebase to your project.