What problem does it solve? Distributing updates for macOS apps outside the Mac App Store requires manual infrastructure for update checking, signing, and delivery. This Skill guides the complete integration of the Sparkle framework so a native macOS app can check for, download, and install updates automatically. ## Core Features & Use Cases - Sparkle SPM Integration: Adds the Sparkle 2.x package dependency and configures Info.plist keys including SUFeedURL and SUPublicEDKey. - UpdaterManager Singleton: Provides a ready-to-use Swift singleton wrapping SPUStandardUpdaterController with DEBUG-build guards, Combine-based UI binding, and menu-bar app activation policy handling. - Appcast & Signing Setup: Covers EdDSA key generation, initial appcast.xml creation, and the release item format with sparkle:edSignature enclosures. - Use Case: You are shipping a menu-bar macOS app via GitHub releases and need a "Check for Updates" button in settings that securely delivers signed updates through a hosted appcast feed. ## Quick Start Add Sparkle auto-update support to my macOS app with a Check for Updates button and an appcast feed hosted on GitHub.