Other (Mobile) covers mobile-development topics outside the major frameworks — Flutter (which has its own dedicated category in larger taxonomies), Kotlin Multiplatform Mobile (KMM), Jetpack Compose, SwiftUI, native iOS Objective-C / Swift, and the increasingly common pattern of mobile-only product engineering at consumer-app companies.
The skills that span all platforms are the architectural ones: state management, offline-first sync, push-notification design, app-store submission and review processes, and the operational layer of mobile (crash reporting, OTA updates, A/B testing flags, gradual rollouts via TestFlight or staged Play Store rollouts).