firefox-extension
Installation
SKILL.md
Firefox WebExtension Development
Complete reference for building, testing, and publishing browser extensions for Mozilla Firefox.
Overview
Firefox extensions use the WebExtensions API with the browser.* namespace (Promise-based natively). Firefox supports both Manifest V2 and V3, with MV2 NOT deprecated (unlike Chrome).
Key Characteristics:
- Global namespace:
browser(Promise-based) - Both MV2 and MV3 supported
- Firefox-specific APIs:
sidebarAction,userScripts,contextualIdentities,protocol_handlers - Submission via AMO (addons.mozilla.org)