Chapter 2. Debian kernel source
kernel-team.pages.debian.net › ch-sourceThe Debian version of the kernel packages has the form version-revision where version is the upstream version of the kernel (like 3.2.20) and revision determines the patchlevel. For example, the packages with version 3.2.20-1 are built from the linux_3.2.20.orig.tar.xz source, patched up to patchlevel 1.