$ git clone -n https://src.fedoraproject.org/rpms/rubygem-syck.git /var/lib/mock/f41-build-846643-163162/root/chroot_tmpdir/scmroot/rubygem-syck
Cloning into '/var/lib/mock/f41-build-846643-163162/root/chroot_tmpdir/scmroot/rubygem-syck'...
$ git fetch origin 0b6fa37a6eb5b3412a3d0c09134141f6fb9cfa1f:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-syck
 * [new ref]         0b6fa37a6eb5b3412a3d0c09134141f6fb9cfa1f -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 0b6fa37 1.5.1.1