The kernel-FLAVOUR-extra packages are also mentioned in the docs and release notes, as "unsupported and not on the installation media".
But they also seem to be missing in all the online repositories for SLES - or at least the ones we have access to.

Maybe there's an Extra repository (like with SLES11) that has not yet been activated. If this is the case, then this should also be documented in the release notes.

Best Regards