Hi,
Almost every German military vehicle is equipped with it. It‘s a so-called „Leitkreuz“ which literally means "guiding cross" and is part of the blackout lighting system that is used under battle or manoeuvre conditions at night.
In the middle of the cross is a lamp, that illuminates the cross. The Leitkreuz is used as a guidance for following vehicles when driving in a convoy.
Hoping that I could throw some light on.
Cheers
Matty