With nvim's terminal mode, if it had the ability to detach and reattach, it could serve as a replacement for screen or tmux.

This would require a few additional bits:

• A :detach function, to stop running the text UI and daemonize into a --headless instance that will survive the current user session ending.
• A command-line argument to list running nvim instances.
• Command-line arguments to attach to a running nvim instance and start the text UI. These need three variations: one that just fails if the session already has an attached text UI, one that detaches any attached text UI first (like screen -D -R), and one that attaches without detaching any other attached text UI (like screen -x). (That last one is optional, but I'd find it quite useful.)

cc @jameysharp