Stay Safe !!
Actually, theres an interesting story behind them. A Jewish Chaplain was at the barracks in Beirut when it was bombed in 83. He used his kippa (yarmulke) to stem a Marines bleeding. A Catholic Chaplain observed this, and cut the Rabbi a new one from his own camo uniform. The story is said to have made the rounds and led to legislation allowing the wearing of religious items while in uniform, and later kosher (halal too) MREs.
If I can find a link Ill post it.