Apparently it means that it has a certain amount of time before it has to be swapped out. I cannot remember if it is 750 hours or 950. That from an engineer who I trust implicitly.
Found it in the latest FCOM. SYS Lights - Exterior lights in the controls and indicators section.
A blue light below each strobe light allows to monitor the strobe light wear (LED technology). When STROBE sw is
OFF or BEACON sw is ON, this light flashes in blue if the strobe light replacement should be planned.
There is also one on the nav lights as well
blue light below each navigation light allows to monitor the navigation light wear (LED technology). When the NAV
& LOGO sw is ON, this light flashes in blue if the navigation light replacement should be planned.
Doesn't mention a time limit and I don't have a maintenance manual to look it up in.