That notwithstanding, some dauntless cookbook writers will still offer you recipes for Mulligan Stew.
It’s not certain where the name came from. General theory has it originating in America, in the hobo and tramp camps that started in the early 1900s and reached their peak during the depression. The rule of the camp tribe was that at meal time everyone pitched in whatever s/he had managed to come across, and a camp cook would stew it all up in a huge pot. The romance has the stews being cooked up over open fires, and served in tin cups — which were often just tin cans.
The name Mulligan probably evolved because America has always cherished a fondness for “down on their luck” Irish people, with Bing Crosby movie charm rolled in. As an Irish name, Mulligan would have conjured up a fonder image than “bum” or “tramp” stew.