This function indicates if "lap" function (lap number) is active.
When "lap" is not lit up, this means that the function has been switched off.
The "lap" function can be activated using the "lap" function of the setting menu.

Riding mode set indication
Riding style function (riding style change)Checking and adjusting timing belt tension
Note
The on-screen icons used during this procedure are explained in a table at
the end of this section.
Note
This operation, which is performed using the dds diagnosis instrument, has
the advantage that it can be carried out on
both timing belts with the engine still installed on the frame. ...
Appropriate diagnosis tools
97900.0211 Dds (ducati diagnosis system) without cables
97900.0227 Power cable and diagnosis
97900.0222 Power cable and diagnosis 1060838 (measurement module)
97900.0218 Vacuum sensor
552.1.039.1A Pressure sensor
97900.0220 Pressure/vacuum tube
97900.0221 Union
...
On/off switch on handlebar
Introduction
The on/off switch on the handlebar is used to switch the dashboard on and
off, if a key has been detected, and start the
engine.
With the switch turned to "run off" (centre position), pushing downwards
switches the dashboard on or off (activating
the button inside the switch). ...