This is used to delimit paths in the DM code tree. A path beginning with ’/’ is an absolute path (which is independent of where in the code it is used). Otherwise, a path is relative, meaning it starts from the current position in the code.
The following example uses a path in the code tree to define the type of object to create when leaving a corpse behind.
obj
var
poison
nutrition
corpse
frog
nutrition = 10
spider
nutrition = 6
poison = 5
mob
var
corpse = /obj/corpse
Die()
new corpse(src.loc) //create the corpse here
del src
spider
corpse = /obj/corpse/spider
frog
corpse = /obj/corpse/frog