$ git clone -n https://src.fedoraproject.org/rpms/perl-Sereal.git /var/lib/mock/f38-build-side-42-init-devel-844419-28419/root/chroot_tmpdir/scmroot/perl-Sereal
Cloning into '/var/lib/mock/f38-build-side-42-init-devel-844419-28419/root/chroot_tmpdir/scmroot/perl-Sereal'...
$ git fetch origin 18c66309958d50bd8ca8a049bd4e9468dad623bf:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-Sereal
 * [new ref]         18c66309958d50bd8ca8a049bd4e9468dad623bf -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 18c6630 Update to 5.003 (rhbz#2168014)