Where does “brett” come from?

brett (German) comes from Middle High German bret, from Old High German bret, from Proto-West Germanic *bred, from Proto-Germanic bredą, from Proto-Germanic bʰredʰóm, from Proto-Indo-European bʰer-dʰ-, from Proto-Indo-European bʰer- — to bear, carry.

brett (German): board, plank