$ git clone -n https://src.fedoraproject.org/rpms/fedora-repro.git /var/lib/mock/f45-build-8875-396/root/chroot_tmpdir/scmroot/fedora-repro
Cloning into '/var/lib/mock/f45-build-8875-396/root/chroot_tmpdir/scmroot/fedora-repro'...
$ git fetch origin 977e0ad615f1fddcbbce17ed6c80c9d9a2a1a7d4:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/fedora-repro
 * [new ref]         977e0ad615f1fddcbbce17ed6c80c9d9a2a1a7d4 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 977e0ad Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild