Complex sentence: It is not clear whether they are separate forms of the gods Baal and El, or are actually one god, nor what covenant or covenants are referred to by the name "Berith".
Split into simpler sentences: It is not clear whether Baal-berith and El-berith are separate forms of the gods Baal and El or are actually one god. Also unknown is what covenant or covenants are referred to by the name "Berith".