Comment # 28 on bug 1166406 from Ludwig Nussel

get_kernel_version works fine with vmlinuz too:

# for i in /boot/vmlinu*; do echo -n $i:; get_kernel_version $i; done
/boot/vmlinux-5.6.0-1-default.xz:/boot/vmlinuz:5.6.0-1-default
/boot/vmlinuz-5.6.0-1-default:5.6.0-1-default

Wrt the open question about how to install the package containing vmlinux. I
guess what you want is to install that package if both kernel-default as well
as kernel-default-debuginfo are installed. You can use boolean deps� for that.

So in kernel-default something like that should work:
Requires:       (%name-vmlinux = %version-%release if %name-debuginfo =
%version-%release)

[1] https://rpm.org/user_doc/boolean_dependencies.html