$ git clone -n https://src.fedoraproject.org/rpms/apache-commons-codec.git /var/lib/mock/f42-build-3403675-45135/root/chroot_tmpdir/scmroot/apache-commons-codec
Cloning into '/var/lib/mock/f42-build-3403675-45135/root/chroot_tmpdir/scmroot/apache-commons-codec'...
$ git fetch origin 3d56f6f5a6891cd61f05c67bef5c658e66de66a5:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/apache-commons-codec
 * [new ref]         3d56f6f5a6891cd61f05c67bef5c658e66de66a5 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 3d56f6f Remove javadoc subpackage