1)
What is the significance of Batzrah?
1.
Rashi: It is between Edom and Mo'av. It is from Mo'av, but it was drawn after Edom, and it established a king for Edom ("Yovav ben Zerach mi'Batzrah" ? Bereishis 36:33) after their first king died.
2.
Malbim: It is the great city of Edom. Romi is in place of it. Yeshayah prophesized about it "Mi Zeh Ba me'Edom Chamutz Begadim mi'Batzrah" (63:1).