Ho hum, more rare manuscripts

Ok, so they're only copies Bach made of Dietrich Buxtehude and Johann Adam Reinken's music, not some brand new discovery by a giant, but doesn't it seem like there's a new manuscript by a one of the Great Masters found every few weeks these days? Of course, my desk being in the state it's typically in, I can understand losing paperwork, but a Bach score? Here's the Bach manuscript copies story via the BBC.