$ git clone -n https://src.fedoraproject.org/rpms/rebase-helper.git /var/lib/mock/f45-build-34397-686/root/chroot_tmpdir/scmroot/rebase-helper
Cloning into '/var/lib/mock/f45-build-34397-686/root/chroot_tmpdir/scmroot/rebase-helper'...
$ git fetch origin 7148ae76b2c730e1ed9eba5eef5c4b25ad995ed4:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rebase-helper
 * [new ref]         7148ae76b2c730e1ed9eba5eef5c4b25ad995ed4 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 7148ae7 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild