The crescent identifies the box's contents as rations in the military supply chain, and readily distinguishes it from other classes of supplies. It is the US and NATO symbol for Class I supplies (rations). read more
The crescent, used as a mark on Army rations during the last century, relates to subsistence. Alas, it doesn’t say why it relates. An oft-quoted source is this post: Black Crescent Rations Symbol. read more