Could it be this? https://www.udeuschle.de/panoramas/makepanoramas.htm
replyNo, it used a much heavier JS interface and IIRC it also used Google Earth. That is a nice tool, thanks for sharing it.
replyIt was https://caltopo.com/
replyhttps://www.heywhatsthat.com/ is another bookmark that I had lost to time.
heywhatsthat?
replyI think that was it, thank you for finding it again!
replyActually, I was thinking of https://caltopo.com/map.html but your site led me to it.