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)Reassembly of the connecting rods
Before starting, check that the crankshaft main bearing journals and big-end
journals are free of burrs or evident signs of
machining: if necessary, clean the surfaces with very fine emery cloth and oil.
Check that the grooves are in perfect condition with no signs of forcing.
Clean the cra ...
Removal of the exhaust system
Remove the silencer, as described in the paragraph "removing the silencer" of
this section.
Loosen the screws (28) and remove the exhaust by-pass valve cover (27).
Turn the exhaust valve pulley (a) to facilitate the throttle cable (25)
output.
Release the end fitting (b) of the cable ...
Traction control (dtc) deactivated
The activation of this (amber yellow) "warning" indicates
that dtc (ducati traction control) has been turned off.
Note
In this case, ducati recommends being very careful
when riding as the vehicle behaviour will be different in
comparison to when operating with the traction control
...