$ git clone -n https://src.fedoraproject.org/rpms/perl-MCE.git /var/lib/mock/f39-build-1438786-32225/root/chroot_tmpdir/scmroot/perl-MCE
Cloning into '/var/lib/mock/f39-build-1438786-32225/root/chroot_tmpdir/scmroot/perl-MCE'...
$ git fetch origin 4dc9d3cccfc8c98c19c00db88634dd90d2dc7fb2:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-MCE
 * [new ref]         4dc9d3cccfc8c98c19c00db88634dd90d2dc7fb2 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 4dc9d3c Update to 1.889 (rhbz#2238875)