Ionic (Angular/React/Vue front end), Capacitor/Cordova plugin ecosystem and bridge behavior (JS native), WebView rendering (WKWebView) nuances, and offline/online hybrid flows.
iOS (Swift) basics needed for black box/gray box validation: view lifecycle, networking, push notifications, background modes, Keychain, and deep links/universal links.
Plugin Testing : validating Capacitor/Cordova plugins (Camera, Geolocation, Push, Filesystem, In App Purchases, Biometric/Auth), permission prompts, and error states.
Build & Packaging Awareness : Xcode schemes, provisioning profiles, signing, TestFlight distributions; Podfile/SPM dependencies for iOS; understanding how Web assets are bundled in Ionic builds.