I try to understand the structure of the ubuntu kernel-ppa since I need to upgrade my vanilla kernel. Given the MainlineBuild manual, there exist three packages for installation (e.g. in 4.15.18):
linux-headers-*-generic-*-alllinux-headers-*-generic-*-<arch>linux-image-*-generic-*-<arch>
But that is not true for all builds (e.g. 4.14.39 has four packages):
linux-headers-*-generic-*-alllinux-headers-*-generic-*-<arch>linux-image-unsigned-*-generic-*-<arch>linux-modules-*-generic-*-<arch>
What's the deal behind this structure, since it is not explained in the MainlineBuild manual?
Are all modules in unsigned kernels build out-of-tree?
What is the benefit and how to install these unsigned kernels properly?