In tmux, is there a way to list unbound keys?

Question

I know it's easy to list all keybindings in tmux, for example with prefix ? or tmux list-keys, but I want to get a list of all keys that are not yet bound to anything, to more easily see what is available for things I'm adding.

Does tmux provide any way to do that?

Answer 1

I haven't worked out all the details, but it would be possible to take

1. a list of all keys supported by tmux
2. a list of all keys currently bound, with something like tmux list-keys -a -N -T prefix | awk '{ print $1 }', and
3. use comm to remove bound keys and leave all unbound keys.

It would be better if tmux itself could give us this list, since that would be more reliable, however.