the required linux-kbuild package is absent in the sid

[Dmitry Oboukhov <linuxover@gmail.com>]

Sometimes I want to install the newest kernel. I write the sid's repo
in my /etc/apt/sourses.list and try to install the latest version of
kernel.

After that I remember about my loop-aes and vboxdrv modules and so I
try to install the linux-headers package. But this effort fails: the
required linux-kbuild package is absent in the sid.

I am an unlucky person [*],
but this situation repeats every time if I want to install the newest
kernel.

If I wait a few days then the situation is resolved.

Could anybody tell me why an upload of a new linux-image always [*]
goes before linux-headers and linux-kbuild?