$ git clone -n https://src.fedoraproject.org/rpms/pdfmixtool.git /var/lib/mock/f39-build-1583789-38129/root/chroot_tmpdir/scmroot/pdfmixtool
Cloning into '/var/lib/mock/f39-build-1583789-38129/root/chroot_tmpdir/scmroot/pdfmixtool'...
$ git fetch origin 85248896f70e0089f922284e5e0a55d8e2b55c14:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/pdfmixtool
 * [new ref]         85248896f70e0089f922284e5e0a55d8e2b55c14 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 8524889 Fix FTBFS (rhbz#2226083)