$ git clone -n https://src.fedoraproject.org/rpms/jflex.git /var/lib/mock/f42-build-3355561-45025/root/chroot_tmpdir/scmroot/jflex
Cloning into '/var/lib/mock/f42-build-3355561-45025/root/chroot_tmpdir/scmroot/jflex'...
$ git fetch origin 9c3a0047c76bee65149b6c6eb56f9e7f2a95509d:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/jflex
 * [new ref]         9c3a0047c76bee65149b6c6eb56f9e7f2a95509d -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 9c3a004 Remove javadoc subpackage