$ git clone -n https://src.fedoraproject.org/rpms/perl-Ref-Util-XS.git /var/lib/mock/f41-build-815983-149916/root/chroot_tmpdir/scmroot/perl-Ref-Util-XS
Cloning into '/var/lib/mock/f41-build-815983-149916/root/chroot_tmpdir/scmroot/perl-Ref-Util-XS'...
$ git fetch origin 7cdcdd3b102ccc1d4ce2f9f222a796085477f129:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-Ref-Util-XS
 * [new ref]         7cdcdd3b102ccc1d4ce2f9f222a796085477f129 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 7cdcdd3 Perl 5.40 rebuild