Hey! Thank you very much! 🙏 Main Menu -> Load -> Export will download a .save file. You can import it by pressing Import in the top right corner in the same window. Importing the IndexedDB dump should work as well though but it's not ergonomical.
Yeah, lots of issues in Firefox with color profiles and the anti-fingerprinting things where it fails reading the map since the colors won't match. Haven't found a reliable fix yet that works on all platforms (e.g. when it started working on Firefox Windows it stopped working on Firefox Linux etc).
Oh, I haven't noticed the Export button. Exported .save is almost exactly the same JSON as dumped IndexedDB data. Anyways, I learned something.
I do use Linux. Currently I get error: "Unknown color in blueprint (case #1): 255, 255, 251". Previously it was something like "w is undefined". Really looks like something with loading colors.