Design, build, port, debug, test, or prepare browser extensions for Chromium, Firefox, and Safari using the WebExtensions model. Use when work involves manifest.json, Manifest V3, extension service workers or background scripts, content scripts, extension messaging, browser permissions, toolbar actions, options pages, sidebars, cross-browser extension compatibility, store-ready packages, Chrome Web Store, Firefox Add-ons, or Safari Web Extensions. Also use when migrating an existing extension between browsers.
