2.6.23-rc6-mm1, "This Just Isn't Working Any More"
A frustrated sounding Andrew Morton released the 2.6.23-rc6-mm1 kernel as "a 29MB diff against 2.6.23-rc6." Many patches are merged first into Andrew's -mm tree for testing before being pushed to Linus' mainline tree during the merge window.
Andrew suggested that the -mm process wasn't working as well as it could:
"It took me over two solid days to get this lot compiling and booting on a few boxes. This required around ninety fixup patches and patch droppings."