Zellij is a high-craft terminal multiplexer written in Rust, offering a client-server architecture with native and web clients. It manages terminals, panes, tabs, and sessions with full VT emulation, mouse support, and a plugin system based on WebAssembly. The server handles panes (tiled, floating, stacked), PTY I/O, scrollback, search, sixel/Kitty graphics, and session serialization for resurrection. Plugins (built-in: bars, strider, configuration, prompt, session-manager, etc.) extend the UI via a widget framework with serialization through ANSI DCS escapes. The client processes keyboard/mouse input, provides a web client with xterm.js and WebSocket transport, and supports remote attach with token-based auth. The codebase is exceptionally well-tested (unit + integration test suites, snapshot-based), with clean trait abstractions (ClientOsApi, ServerOsApi, ZellijPlugin) and a custom build system (xtask). It is not a data/research repository.