$ git clone -n https://src.fedoraproject.org/rpms/R-covr.git /var/lib/mock/f40-build-760515-121099/root/chroot_tmpdir/scmroot/R-covr
Cloning into '/var/lib/mock/f40-build-760515-121099/root/chroot_tmpdir/scmroot/R-covr'...
$ git fetch origin a470aeb38895fb96fb1f8704cb4046cf872736ac:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-covr
 * [new ref]         a470aeb38895fb96fb1f8704cb4046cf872736ac -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at a470aeb 3.6.4