$ git clone -n https://src.fedoraproject.org/rpms/R-reticulate.git /var/lib/mock/f42-build-3530697-46321/root/chroot_tmpdir/scmroot/R-reticulate
Cloning into '/var/lib/mock/f42-build-3530697-46321/root/chroot_tmpdir/scmroot/R-reticulate'...
$ git fetch origin f681586987b34b78d67cb096c0567c13d33bfafb:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-reticulate
 * [new ref]         f681586987b34b78d67cb096c0567c13d33bfafb -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at f681586 Rebuild