$ git clone -n https://src.fedoraproject.org/rpms/R-ncdf4.git /var/lib/mock/f42-build-side-1-3498654-45963/root/chroot_tmpdir/scmroot/R-ncdf4
Cloning into '/var/lib/mock/f42-build-side-1-3498654-45963/root/chroot_tmpdir/scmroot/R-ncdf4'...
$ git fetch origin 7b178811c0c348b3d5450098a75281cb5f603283:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-ncdf4
 * [new ref]         7b178811c0c348b3d5450098a75281cb5f603283 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 7b17881 R-maint-sig mass rebuild