Mark, a change in conditions or flight plan route causes predicted fuel at destination to be 900kg or 2000 lbs or less.

The corrective action by the crew is to modify the rte plan or cruising altitude, or divert for additional fuel.

It is a significant message of the "Alerting category" also bring an amber light on the nd

I should have written, the message will light ( or should light ).
Tonite, I made a flight with my 757. deep in the flight, my fuel prediction
at destination was 9.2 - 9.3  perfect. Then some good tail wind made me gain fuel to 10.6 - the message lit up ????? I cleared the message.

It is an FMC prediction of the remaining fuel at destination. By then you would be deep into the reserve and risking out of fuel.
There is no message that I know for " out of fuel"!!!!!!!!!   :o

Raymond   Boeing or nothing
KFLL   South Florida