$ git clone -n https://github.com/xcp-ng-rpms/kernel-4.9 /var/lib/mock/dev-testing-335-100/root/chroot_tmpdir/scmroot/kernel-4.9
Cloning into '/var/lib/mock/dev-testing-335-100/root/chroot_tmpdir/scmroot/kernel-4.9'...
$ git reset --hard 15aa714
Downloading SOURCES/kernel-exp-4.9.135.tar.gz (144 MB)
HEAD is now at 15aa714 Update to 4.9-156.1 (#9)