This icon only appears in Abraham Washington's infobox the outfit selection pane shows no icon, name, or bonus. Despite the fact that the in-game Washington is wearing a blue shirt with a green pullover, the outfit's icon is the same white, long-sleeve, button-down shirt icon that a new dweller has before he is brought into the vault.
The content is not described in full detail on this page.
This page lists all characters in Fallout Shelter. The following is based on information from Fallout Shelter or Fallout Shelter Online.