A tmux plugin that displays a helpful cheatsheet
prefix + M-?
which is most likely
prefix + Alt-?
If you are using the default prefix, then the shortcut key will be
C-b + Alt-?
If you are using tmux-sensible, then the shortcut key will be
C-b + Alt-?
Cheatsheet information adapted from https://gist.github.com/andreyvit/2921703.