vmlinuz-2.6.32-trunk-amd64?

["Thomas H. George" <lists@tomgeorge.info>]

I find I now have vmlinuz-2.6.32-trunk-amd64 in my boot directory.
Added, I guess, as part of a recent dist-upgrade though I didn't notice it
(careless) in the list of new items to be installed.

grub has added this kernel image to the top of the boot list but trying
to boot with it ends in kernel panic, can't find root directory.  This
is not catastrophic as the system still boots and functions perfectly
with vzlimuz-2.6.30-2-amd64.

I assume this will be corrected in due course but I am curious, what is
the significance of the trunk designation?