$ git clone -n https://src.fedoraproject.org/rpms/mcstrans.git /var/lib/mock/f42-build-867538-175616/root/chroot_tmpdir/scmroot/mcstrans
Cloning into '/var/lib/mock/f42-build-867538-175616/root/chroot_tmpdir/scmroot/mcstrans'...
$ git fetch origin 4f9075fe9cf0ebee822db873a816622f13d80f0d:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/mcstrans
 * [new ref]         4f9075fe9cf0ebee822db873a816622f13d80f0d -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 4f9075f SELinux userspace 3.8-rc3 release