The feature is detailed via the following option:
--alert none|bell|blink
Set alert action on connect/disconnect.
It will sound the bell once or blink once on successful connect.
Likewise it will sound the bell twice or blink twice on disconnect.
Default value is "none" for no alert.
Make it possible to remap the prefix key (default: ctrl-t) by setting
the prefix-ctrl-key variable in the configuration file.
Allowed values are in the range a..z.
Example, to set the prefix key to ctrl-a simply do:
prefix-ctrl-key = a