Hanafi
The sources give no view for it here.
حكم الوجوب
هل هي واجبة؟
Each school’s answer
Hanafi
Not stated in the sources
Maliki
Not stated in the sources
Shafi'i
حكمها واجبة في أظهر القولين
واجبةHanbali
Not stated in the sources
The texts
واختلفوا في وجوبها واختلفوا في وجوبها. فقال الشافعي وحدة: هي واجبة في أظهر القولين عنده.
«الإفصاح», Ibn Hubayra p. 604
From the schools’ own books
Maliki
The sources give no view for it here.
Shafi'i
واجبةIts place in the school’s books is not linked yet.
Hanbali
The sources give no view for it here.
What bears this mark is in our words, our standard wording; the books’ texts stay as they are.