$ git clone -n https://src.fedoraproject.org/rpms/R-qpdf.git /var/lib/mock/f42-build-side-1-3583459-46888/root/chroot_tmpdir/scmroot/R-qpdf
Cloning into '/var/lib/mock/f42-build-side-1-3583459-46888/root/chroot_tmpdir/scmroot/R-qpdf'...
$ git fetch origin 3c2db8a263e73c2185b96604aca0515c9754777b:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-qpdf
 * [new ref]         3c2db8a263e73c2185b96604aca0515c9754777b -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 3c2db8a Update to 1.4.0 upstream release