What does "everything but the kitchen sink" mean?

Also, everything under the sun. Including just about everything, whether appropriate or not. For example, Our new car has every feature—everything but the kitchen sink. This hyperbolic term may date from the early 1900s but only became widespread in the mid-1900s. The variant employs under the sun in the sense of “everything on earth,” a usage dating from about a.d. 1000.