Possible meanings are 1) Mamre was another name for Hebron or 2) Hebron was formerly called Mamre or 3) Mamre was very near the larger city of Hebron, so people usually called it Hebron.
Here "sons" stands for those who descended from Heth. See how you translated this in [Genesis 23:3](./03.md). AT: "the descendants of Heth" (See: [[rc://en/ta/man/translate/translate-names]])