Around 1910 a Connerré charcutier, Albert Lhuissier, sold rillettes sandwiches to train crews and then passengers when the Paris-Brest train stopped, helping make Le Mans rillettes famous.
Pork cooked slowly in its own fat, shredded into a rich spread and packed into a baguette; sold by weight at Sarthe charcuteries and eaten mostly in sandwiches.
Why it's made this way: Rillettes began in neighbouring Touraine, but Le Mans and the Sarthe made them a nationally known product once the railway reached Paris markets, and Connerré became known as the rillettes capital of the Sarthe.