This kernel is the same as the kernel-huge from slackware.

kernel-$KVER-$ARCH-1dj.txz has everything included kernel, modules, firmware and source. 

If you want to have all above in saparate packages then do not install the above package and install these
kernel-custom-$KVER-$ARCH-1dj.txz includes the kernel
kernel-custom-modules-$KVER-$ARCH-1dj.txz includes the modules
kernel-custom-firmware-$KVER-$ARCH-1dj.txz includes the firmware
kernel-custom-source-$KVER-noarch-1dj.txz includes the source need to compile new kernel modules e.g. virtualbox, vmware


If you want to build the packages by your own then
1. If you run a different kernel
download and install fake-uname package from http://people.salixos.org/djemos/salix/fake-uname/fake-uname-0.1-noarch-1cp.txz
sudo spkg -i fake-uname-0.1-noarch-1cp.txz
sudo passwd root
su
fake-uname-activate $KVER e.g.  fake-uname-activate 4.4.2
and proceed to 2.


2. 
extract linux-src 
sudo tar xvf linux-4.4.2.tar.xz -C /usr/src

build the packages
fakeroot slkbuild -X