GreenTunnel is a local proxy that bypasses DPI (Deep Packet Inspection) censorship by fragmenting the TLS ClientHello so the SNI never appears whole in a single packet, and by resolving DNS over encrypted channels (DoH/DoT). It is a ground-up TypeScript rewrite of the original GreenTunnel, fixing numerous bugs from v2 (backpressure, timeouts, HTTP framing corruption, DNS cache expiry, system proxy crash safety). The repository is a monorepo containing a core engine library, a CLI tool (`gt`), and an Electron desktop app. The engine implements a full HTTP/HTTPS proxy with TLS fragmentation, HTTP request rewriting (absolute-form to origin-form), a caching DNS resolver with TTL-based expiration and in-flight deduplication, and a system-proxy management layer with snapshot/restore and crash recovery. The desktop app provides a 340px frameless window with a live log panel (virtual list), tray integration, and non-intrusive advocacy prompts. The codebase is exceptionally well-documented (CLAUDE.md serves as the authoritative design document), uses modern Node.js features (parseArgs, styleText, pipeline), and has a strong emphasis on correctness and edge-case handling (e.g., stranded proxy detection, HTTP framing awareness, signal handling for clean shutdown).