$ git clone -n https://src.fedoraproject.org/rpms/R-iterators.git /var/lib/mock/f45-build-6169-346/root/chroot_tmpdir/scmroot/R-iterators
Cloning into '/var/lib/mock/f45-build-6169-346/root/chroot_tmpdir/scmroot/R-iterators'...
$ git fetch origin 1b5e184d79671fcd8dd168ad80df4fab4913888f:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-iterators
 * [new ref]         1b5e184d79671fcd8dd168ad80df4fab4913888f -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 1b5e184 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild