Extended General Line and Sector Types system

XG, short for "Extended General Line and Sector Types system", is a system in the Doomsday and Risen3D source ports that allow the user to create new line and sector types (including triggers that perform several different actions on different areas of the map). It is not actually a scripting language; one could consider it a considerably more powerful and flexible, but more complicated, version of Boom's "Generic linedef types".