$ git clone -n https://src.fedoraproject.org/rpms/R-qpdf.git /var/lib/mock/f42-build-side-1-3588864-46950/root/chroot_tmpdir/scmroot/R-qpdf
Cloning into '/var/lib/mock/f42-build-side-1-3588864-46950/root/chroot_tmpdir/scmroot/R-qpdf'...
$ git fetch origin a1be58519a1d03a37ecfbb44757734d2f56c35d4:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-qpdf
 * [new ref]         a1be58519a1d03a37ecfbb44757734d2f56c35d4 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at a1be585 Update to 1.4.1 upstream release