The Australian Liberation Front was a renegade organization consisting of the settlers in the Outback. After the Omnic Crisis, their lands were given to the Omnics by way of a peace treaty, the settlers living upon the grounds displaced. Angered, they joined together to form the ALF, its members including the likes of Roadhog prior to his irradiation.
The ensuing battles with the robots eventually culminated in the destruction of their fusion core, obliterating the landscape and leaving it bathed in radiation for generations to come. The ALF seemed to dissolve afterward, some of its members joining the collection of survivalists known as the Junkers.