$ git clone -n https://src.fedoraproject.org/rpms/R-git2r.git /var/lib/mock/f38-build-725232-99560/root/chroot_tmpdir/scmroot/R-git2r
Cloning into '/var/lib/mock/f38-build-725232-99560/root/chroot_tmpdir/scmroot/R-git2r'...
$ git fetch origin d579a1379877e9b2ee83558b130f769ba044ac06:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-git2r
 * [new ref]         d579a1379877e9b2ee83558b130f769ba044ac06 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at d579a13 update to 0.32.0