$ git clone -n https://src.fedoraproject.org/rpms/R-ggplot2.git /var/lib/mock/f40-build-2168966-50976/root/chroot_tmpdir/scmroot/R-ggplot2
Cloning into '/var/lib/mock/f40-build-2168966-50976/root/chroot_tmpdir/scmroot/R-ggplot2'...
$ git fetch origin dec442cbb10f4af60e032b1b2ff2cc542c43820c:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-ggplot2
 * [new ref]         dec442cbb10f4af60e032b1b2ff2cc542c43820c -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at dec442c Update to 3.4.3