$ git clone -n https://src.fedoraproject.org/rpms/perl-CPAN-Checksums.git /var/lib/mock/f45-build-21969-589/root/chroot_tmpdir/scmroot/perl-CPAN-Checksums
Cloning into '/var/lib/mock/f45-build-21969-589/root/chroot_tmpdir/scmroot/perl-CPAN-Checksums'...
$ git fetch origin bff3a2fa8358d7b60c3f90f84296b51657eb4e76:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-CPAN-Checksums
 * [new ref]         bff3a2fa8358d7b60c3f90f84296b51657eb4e76 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at bff3a2f Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild