The Bronsons are four Named Enemies in DLC3 of Borderlands 3. Adelai, Cal, Degan and Kender Bronson are on the “Most Wanted” list. The Bronsons are located in The Blastplains on the Planet Gehenna. You will encounter them near Vorducken.
You can farm Adelai Bronson for the Brightside as it is the dedicated loot source for this item. The Brightside has a 33% drop chance.