Brotherhood Fatigues is an Outfit in Fallout 76. These are items equipped cosmetically by the player "on top" of their armor. This feature is unique to this fallout game, and is meant to promote individuality and provide freedom for players to express themselves and role-play their characters.
How to get Brotherhood Fatigues
You can find this outfit in Thunder Montain Power Plant, Security Building Locker Room. Also the reward for completing Defiance has Fallen questline in Brotherhood of Steel
Brotherhood Fatigues Notes & Tips