These verses, like Deuteronomy 2:10-12, are in all likelihood an addition made by a later reviser.
Zamzummims - A giant race usually identified with the Zuzims of Genesis 14:5.
The Avims which dwelt in Hazerim, even unto Azzah - Read (Gaza, of which Azzah is the Hebrew form. “Hazerim” is not strictly a proper name, but means “villages,” or “enclosures,” probably such as are still common in the East. The Avims are no doubt identical with the Avites of Joshua 13:3, and were doubtless a scattered remnant of a people conquered by the Caphtorim (Genesis 10:14 note) and living in their “enclosures” in the neighborhood of Gerar. The word, which means “ruins,” seems itself expressive of their fallen state.