From the NannyMUD documentation

LAST CHANGE

2001-11-03

NAME

        simul_sfun - Simulated efuns.

DESCRIPTION

	The object /obj/simul_efun provides the game with the
	simulated efuns, i.e. functions that can be used as efuns, but
	are simulated using LPC. It is one of the more important
	objects in the game.