GreenTunnel is a local proxy that bypasses DPI (Deep Packet Inspection) censorship. It works by intercepting HTTPS CONNECT tunnels, detecting the TLS ClientHello, and splitting it into fragments (either TCP segments or valid TLS records) so that the SNI (Server Name Indication) containing the target hostname never appears whole in a single packet. DNS resolution is performed over encrypted channels (DoH/DoT) to prevent ISP-level blocking. The repository contains a complete TypeScript rewrite of the engine, a CLI tool (`gt`), and an Electron desktop app. The engine is deliberately separated from the OS proxy configuration (handled by `SystemProxy`) and from the CLI output, making it testable and crash-safe. The codebase demonstrates strong engineering practices: proper error handling (no silent catch-and-return), backpressure-aware socket writes, framing-aware HTTP request rewriting, and a crash-proof system-proxy snapshot/restore mechanism. The desktop app features a live log panel with virtual scrolling, a tray icon, and a modal star/share prompt scheduled over three asks. The repository is actively maintained with modern tooling (Node 24, TypeScript 6, Electron 43, Vitest 4) and has a comprehensive test suite and CI/CD pipeline.