$ git clone -n https://src.fedoraproject.org/rpms/R-futile.options.git /var/lib/mock/f45-build-6110-346/root/chroot_tmpdir/scmroot/R-futile.options
Cloning into '/var/lib/mock/f45-build-6110-346/root/chroot_tmpdir/scmroot/R-futile.options'...
$ git fetch origin 39dcde2723eec05e7c050622b8bc96f29102f953:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-futile.options
 * [new ref]         39dcde2723eec05e7c050622b8bc96f29102f953 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 39dcde2 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild