$ git clone -n https://src.fedoraproject.org/rpms/fetchlog.git /var/lib/mock/f45-build-8940-397/root/chroot_tmpdir/scmroot/fetchlog
Cloning into '/var/lib/mock/f45-build-8940-397/root/chroot_tmpdir/scmroot/fetchlog'...
$ git fetch origin d12cfff104f5ff1ff60e4688e34247559009e7f8:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/fetchlog
 * [new ref]         d12cfff104f5ff1ff60e4688e34247559009e7f8 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at d12cfff Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild