I printed out one of the Mouse Guard GM Sheets from the Sheet pack that was downloadable from the Wiki, and I noticed there is an area there labeled “Host Family”.
I don’t recall having read about this in the book. I can assume it means “Someone taking care of your Mouse Guard if his real family is dead”, IE whichever family Lieam claims as his own since his parents are dead. Is this correct? Just something to add more flavor to the characters and allow the players to have a heavier hand in crafting the story they want to tell?