$ git clone -n https://src.fedoraproject.org/rpms/reprotest.git /var/lib/mock/f39-build-1845081-42078/root/chroot_tmpdir/scmroot/reprotest
Cloning into '/var/lib/mock/f39-build-1845081-42078/root/chroot_tmpdir/scmroot/reprotest'...
$ git fetch origin b590be81c531d85e32f85721630b6ff50b62336a:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/reprotest
 * [new ref]         b590be81c531d85e32f85721630b6ff50b62336a -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b590be8 version 0.7.26