From https://www.patreon.com/posts/cave-glade-2-0-1-77042624:
It is now possible to get a permalink to a map (Permalink... in the context menu), but you can't use it as a link, not yet. To restore a map, you need to open that form again, paste the saved permalink there and press Generate - same as in my other generators. Later, I'll upload the non-itch version so that permalinks could be used normally.