The Alps seen from the Pyrenees, 381 km away

from the comments on reddit, I landed on this nice website on the same topic [1]

They generate the map of the "visible" panorama from this website [2], but I can't find how they built the KML file that can be seen at the bottom of [1], any idea ? or maybe it's an in-house tool, I can't read Polish !

1: http://www.dalekieobserwacje.eu/alpy-kotyjskie-oraz-nadmorsk...

2: http://www.udeuschle.selfhost.pro/panoramas/makepanoramas_en...