What is the meaning of "al-dhu'abah" (forelock/tassel), what is permissible and impermissible concerning it, and why did scholars mention it in the chapter on qaza' (unevenly shaven hair)? What is the ruling and what are the regulations for opening a beauty salon for women?

The "dhu'aba" is the hair that hangs down from the head, also called "qaza'". The prohibition of "qaza'" refers to shaving a boy's head and leaving a dhu'aba. The various narrations can be reconciled to mean that the permissible dhu'aba is when the hair is let down loose and the rest is braided, whereas the forbidden kind is to shave the entire head and leave only the hair in the middle.