We always used to use brown paper, then newspaper. This was explained to me by the local 'expert', a friend of my grandmother, who made my parents' wedding cake.
Ovens had 'hot' and 'cold' spots. If you left something in for hours, then, even at a low heat, it might 'catch' and this was especially a problem with fruit cakes (as anyone who has ever burned any dried fruit knows!)
So, brown paper first (more hygienic) then newspaper, to insulate the cake a bit from the vagaries of the oven. I haven't done this for some years now as modern ovens are safer and more predictable. My friends with Agas disagree among themselves (!)
I'd like to add that this lovely lady was a Belgian refugee, so everyone thought she understood 'cake' the best! My uncle has a memory of delivering a birthday cake she had made on his bike and having an accident. They had to rush the cake back for an emergency repair job, and summon the one neighbour with a car to deliver it in time!
