Byobu vs GNU Screen

Byobu is a free, GPLv3-licensed text-based window manager and terminal multiplexer for Linux, BSD, and macOS. It runs over tmux or GNU Screen and adds function-key controls, status notifications, profiles, and split-pane layouts. Users can create, rename, reorder, split, zoom, and synchronize windows and panes, then save layouts for restoration or define repeatable window sets in configuration files. Detaching and reattaching preserves windows, processes, and history, with up to 10,000 lines of scrollback per window. A two-line status bar can display CPU, memory, disk, network, battery, load, time, and other indicators, each independently toggleable. The interactive F9 menu changes notifications, keybinding sets, profiles, and backend selection. Byobu defaults to tmux when available but supports GNU Screen and switching through byobu-select-backend. The project requires tmux 1.5 or later and/or GNU Screen. Support is largely volunteer-led through GitHub Issues and StackExchange.

GNU Screen has no write-up on Specifiction yet; its figures are above.