$ git clone -n https://src.fedoraproject.org/rpms/openexr.git /var/lib/mock/f40-build-1965577-25205/root/chroot_tmpdir/scmroot/openexr
Cloning into '/var/lib/mock/f40-build-1965577-25205/root/chroot_tmpdir/scmroot/openexr'...
$ git fetch origin 170ddd8742c68377e5cc63188ca6d40d962711f3:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/openexr
 * [new ref]         170ddd8742c68377e5cc63188ca6d40d962711f3 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 170ddd8 Update to 3.1.13