"Klapmuts" is Dutch and basically means a cap or a hat of a particular shape. The klapmuts was the standard 17th century headgear of the Dutch poor. The less expensive was made out of wool while the more expensive was fashioned of beaver felt.
The shape of this hat is the source of the name for the typical Dutch market soup bowl of the late Ming dynasty, typically in Kraak decoration.
While Chinese food bowls are typically held in one hand while eating the prepared and cutup food with chopsticks, European etiquette prescribed the use of knife for cutting up the food yourself and a large spoon, for soups. For this reason a new bowl shape with a rim for resting the spoon was needed. This shape was eventually developed into what we know as a deep plate.
The rims are in sources explained as for condiments such as mustard while others mention them as for disposing of bones and similar onto.