$ git clone -n https://src.fedoraproject.org/rpms/gscan2pdf.git /var/lib/mock/f41-build-side-1-2951917-35499/root/chroot_tmpdir/scmroot/gscan2pdf
Cloning into '/var/lib/mock/f41-build-side-1-2951917-35499/root/chroot_tmpdir/scmroot/gscan2pdf'...
$ git fetch origin a1d0c4a3be9b89e503ebad1da720e0726cff2647:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/gscan2pdf
 * [new ref]         a1d0c4a3be9b89e503ebad1da720e0726cff2647 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at a1d0c4a 2.13.4 bump