$ git clone -n https://src.fedoraproject.org/rpms/pdfmixtool.git /var/lib/mock/f42-build-61038549-6588101/root/chroot_tmpdir/scmroot/pdfmixtool
Cloning into '/var/lib/mock/f42-build-61038549-6588101/root/chroot_tmpdir/scmroot/pdfmixtool'...
$ git fetch origin c70ac2f1e35a87abce2ce3b967f2e85b5cddba28:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/pdfmixtool
 * [new ref]         c70ac2f1e35a87abce2ce3b967f2e85b5cddba28 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at c70ac2f Update to 1.2.1 (rhbz#2379771)