$ git clone -n https://src.fedoraproject.org/rpms/perl-Variable-Magic.git /var/lib/mock/f45-build-27363-622/root/chroot_tmpdir/scmroot/perl-Variable-Magic
Cloning into '/var/lib/mock/f45-build-27363-622/root/chroot_tmpdir/scmroot/perl-Variable-Magic'...
$ git fetch origin 60a7fa15e81d1574a5ab3e165bccd0adaa218fc4:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-Variable-Magic
 * [new ref]         60a7fa15e81d1574a5ab3e165bccd0adaa218fc4 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 60a7fa1 Update to 0.65 (rhbz#2520627)