$ git clone -n https://src.fedoraproject.org/rpms/R-restfulr.git /var/lib/mock/f38-build-724697-99479/root/chroot_tmpdir/scmroot/R-restfulr
Cloning into '/var/lib/mock/f38-build-724697-99479/root/chroot_tmpdir/scmroot/R-restfulr'...
$ git fetch origin 5dc6f901cf56d4f7aee97088dab6973ae439459d:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-restfulr
 * [new ref]         5dc6f901cf56d4f7aee97088dab6973ae439459d -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 5dc6f90 Fix BuildRequires