kernel sources package has no makefiles

When I used Yast to get the kernel sources, the update
got linux-4.4.120-45 with lots of sources, but no makefiles!
This worked fine last time I did it, maybe the RPMs for this
update got built without the makefiles? Or I’m doing something wrong,
please let me know!

I downloaded kernel-source rpms by hand and opened them in ark, they contain
no makefiles.

kernel-*-devel packages?

If you mean SRPM files (.src.rpm) these are for rebuilding RPM files with the “rpmbuild” command. There are lots of on-line tutorials for building packages with the RPM tools.

They have (almost) nothing to do with using the Gnu C compiler tools with the .tgz archives that come from e.g., sourceforge, github.