Citando a TMUX (1) página de manual:
The -r flag indicates this key may repeat, see the repeat-time option.
E uma pesquisa rápida por repeat-time
gera isso:
repeat-time time
Allow multiple commands to be entered without pressing the prefix-key again in the specified time milliseconds (the default is 500). Whether a key repeats may be set when it is bound using the -r flag to bind-key. Repeat is enabled for the default keys bound to the resize-pane command.