FoxyProxy is a cross-browser extension (Chrome, Firefox, Edge) for advanced proxy management. It allows users to configure individual proxies, use pattern-based proxying (wildcard, regex, match patterns), set proxy per tab or container (Firefox), enable global exclude lists, and manage WebRTC settings. The codebase is highly modular, using ES modules and Manifest V3. It implements single proxy, PAC, and 'proxy by patterns' modes, with features like sync, import/export, a live log, pattern tester, and enterprise policy support. The architecture separates concerns clearly: background service worker handles proxy configuration via browser APIs, options page provides full UX, popup offers quick controls, and context menus add convenience. The code is well-structured, uses modern JavaScript (ES2022), and shows solid engineering practices. Reusable modules include pattern validation, file I/O, and flag display utilities.