$ git clone -n https://src.fedoraproject.org/rpms/R-qpdf.git /var/lib/mock/f42-build-side-1-3535418-46554/root/chroot_tmpdir/scmroot/R-qpdf
Cloning into '/var/lib/mock/f42-build-side-1-3535418-46554/root/chroot_tmpdir/scmroot/R-qpdf'...
$ git fetch origin b6ab45d13e6788293d1b18f36c128f86105a67b0:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-qpdf
 * [new ref]         b6ab45d13e6788293d1b18f36c128f86105a67b0 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b6ab45d Update to latest version (#2178884)