set status_hold_lines [<text>]
This variable sets the string displayed in the status bar when the current window has HOLD_MODE set, and there are queued lines waiting to be displayed. This variable displays the number of lines held (in multiples of 10). If no lines are being held, nothing is displayed.
This string is represented by %B in the STATUS_FORMAT string. It will expand inside STATUS_HOLD_LINES to the number of lines held.
Setting the appearance of the string:
/set status_hold_lines %B
When lines are held, the client will activate this setting and the STATUS_HOLD setting.