Ran across something recently about which I admit I was absolutely ignorant: "trench lights." Came from a German two-seater pilot in a post-war interview:

[Discuss flying an Alb at night to try to shoot down French bombers attacking the airfield] “The next night was better and I found the planes and the Flak and I got in but our Flak never stopped! They were not the lattice type, but the Farman type (Breguet?). They got away and I followed them for quite a distance across the trench lights. By the way how do I know the trench lights? The trench lights you know because they were shooting up these Very pistols all the time. Through the whole line you could see from these lights coming down.”