From Quake Wiki
info_null is a simple point entity that removes itself on map start. It is used as a target for lights in order to set the direction and width of spotlights. Since modern light tools typically support additional keys on lights for improved spotlight control, the info_null entity is largely redundant nowadays.
|targetname||The name of the info_notnull. If the info_notnull is targeted by a light, the light will become a spotlight that faces in the direction of the info_notnull.|
The info_notnull does not support any spawnflags, since it is removed from the level at compile time.