Which recent (27/9 - 1/10) update could break my Grub menu.lst?

I installed Gutsy Beta from the Desktop CD and it all worked perfectly. I have Ubuntu and Windows on this machine and manually edited the grub menu.lst to put Windows above the automatic Ubuntu section (so that it booted by default).

Today, I downloaded all the updates since Gutsy Beta was released. When I rebooted, Windows was missing from the list. Only the various Ubuntu options were there.

I have filed Bug #147524 but I don't know which package to "blame". I see that Grub itself hasn't been updated in that period.

Is there a way of seeing which updates have been applied recently?