This repository contains the iOS client for the ntfy.sh notification service. It is a SwiftUI-based application that allows users to subscribe to topics for receiving push notifications, manage subscriptions, view notifications with attachments, and configure settings. The architecture follows a pattern similar to MVVM using ObservableObjects for state management, with Core Data for persistence and a Notification Service Extension for processing incoming notifications. Key features include Firebase Cloud Messaging integration, attachment handling (download, preview, share, save), critical alerts support, and background polling for notification synchronization. The app supports both the default ntfy.sh server and self-hosted instances.