App was rejected from App Store for violating point 4.2.1 of the App Store Review Guidelines

4.2.1 Apps should use APIs and frameworks for their intended purposes and indicate that integration in their app description. For example, the HomeKit framework should provide home automation services; and HealthKit should be used for health and fitness purposes and integrate with the Health app. Apps using ARKit should provide rich and integrated augmented reality experiences; merely dropping a model into an AR view or replaying animation is not enough.

The unused ARKit code from NextLevel was the reason for rejection. Maybe adding info that using this library without including ARKit functionality in your app will lead to app being rejected would be useful. As an alternative, splitting the library into two versions (with / without ARKit) would be great.