According to Serious Eats, it’s the “Biggest, Baddest Pot of Boiled Meat in the World”! LOL. What I found out from poking around the Internet is that there is a wide range of what people think should go into it. There seem to be many abridged versions: Gordon Ramsay has lentils in his, while Martha Stewart has brisket. Even the more detailed versions have a wide variety of meats. As a rule of thumb, there seems to be beef and sausage and chicken and braising vegetables.
The recipe in the Serious Eats article is pretty detailed, right down to the many sauces you accompany the dish with. If you were having a gathering of hard core meat eaters, it might be a perfect dish to attempt. But otherwise there are simpler stews and other Italian dishes to try and I think I will stick with those.