I think it is one of those things that almost every country will have a variant of - and there will be different variants in different parts of each country too!

So quite fun to try in different places. There are variants in the comments here, or the chatter at Faerie, that include sultanas, raisins, mixed fruit, marmalade, strawberry jam and mincemeat - some with spice, some without, and so on. Also some with plain white bread, some with brioche, some with cinnamon rolls... I guess, in the fist place, you added whatever you had to the stale bread. Nowadays you can use what gives you the best taste!