It just means you have to vacate by the last Friday of your term. Whereas the 40 week contract lets students stay longer, give them time to pack, and don't have to go home immediately.
It is NOT true that you have to vacate the halls of all your stuff over the Christmas and Easter period. The contract just ends three weeks earlier than everyone else.
It's not for nursing and midwifery students as they require a longer contract.
(I've contacted Bangor about this)