Violentmonkey is a mature, open-source browser extension for managing and executing userscripts across Chrome, Firefox, Edge, and other WebExtensions-compatible browsers. The extension provides a full lifecycle for userscripts: installation from URLs or files, automatic updates, syntax-highlighted editing (via CodeMirror 5), per-script configuration, and a dashboard for bulk operations. Its architecture comprises a background service worker (MV3) or background page (MV2), content scripts injected into web pages (with separate realms for page-level GM API execution and content-level bridge), a popup interface, an options dashboard, an installation confirmation page, and an offscreen document for cross-origin requests under MV3. The system integrates multiple sync backends (Dropbox, Google Drive, OneDrive, WebDAV, S3-compatible), supports i18n with 30+ locales via Transifex, and includes custom build tooling for multi-browser packaging. While the core domain is userscript management, the codebase demonstrates sophisticated patterns for secure script injection, anti-spoofing (safe globals), reactive settings, and concurrency-limited storage operations.
This repository is a collection of over 60 simple, installable WebExtension examples, primarily maintained by Mozilla. The codebase is not a single application but a set of independent browser extensions, each in its own directory, demonstrating specific WebExtensions APIs such as tabs, storage, webRequest, menus, and declarativeNetRequest. The examples cover both Manifest V2 and V3, with patterns for background scripts, content scripts, popups, sidebars, and options pages. The repository also includes a shared examples.json metadata file with schema validation, ESLint configuration, and a GitHub Actions workflow for linting and validation. The practical value lies in being a reference and starting point for developers building browser extensions, rather than a production-ready deployable system.