Safari 11 or 12 introduced a new extension system where Safari extensions ship as a macOS app with a Safari extension component that can communicate with the na

Safari 11 or 12 introduced a new extension system where Safari extensions ship as a macOS app with a Safari extension component that can communicate with the native app. And the macOS app has standard Mac Store sandboxing options (by default, no FS access outside of its bundle). I've written some extensions for personal use and so far it's been a great trade-off.