In 1.8 is was possible to display information about unknown triggers in map elements. The functionality was removed in 2.0 but it seems that some of the related code still remains. Code like:

if ($i['unknown'])

{ $info['info']['unknown'] = array( 'msg' => $i['unknown'].' '._('Unknown'), 'color' => $colors['Gray'] ); }

in getMapsInfo(). It should be removed.