$ git clone -n https://src.fedoraproject.org/rpms/perl-Test-HexDifferences.git /var/lib/mock/f45-build-26682-618/root/chroot_tmpdir/scmroot/perl-Test-HexDifferences
Cloning into '/var/lib/mock/f45-build-26682-618/root/chroot_tmpdir/scmroot/perl-Test-HexDifferences'...
$ git fetch origin 9617df119968d87ebd72efec7241b3819b123d9a:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-Test-HexDifferences
 * [new ref]         9617df119968d87ebd72efec7241b3819b123d9a -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 9617df1 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild