Sentence:  These points represent a remnant of the badong or <WSD>backwing</WSD>. In fact, only those characters that wear a <WSD>backwing</WSD> in wayang kulit should have these two points (see page 37, Rahwana). 
Meaning of the word marked with <WSD> tags:  A wing-like projection on the upper back of some a Wayang puppets.