access gog galaxy savegames without installing gog galaxy

I've played a game bought over gog.com and used the savegame cloud of Gog Galaxy, the game was the witcher 3. Now I would like to revisit it and continue from my old savestate. The problem is that on my notebook, I'm running Linux. After quite some configuration, the witcher is now running nicely. But I would like to avoid going through the setup of Gog Galaxy. Is it possible to access the cloud savegames stored in Gog Galaxy without actually installing it?

Unfortunately, while it is possible to download cloud saves, this can (currently) only be done through GoG Galaxy.

According to GoG Support (as of 2019-12-24):

If you want to download a backup copy of your cloud saves, please open the library entry of the game in question, click on "More" and choose "Backups & Goodies" in the drop-down menu. The cloud saves are available under "Cloud Saves Backup Copy". Please note that, section above is available only in GOG GALAXY, not website.

Emphasis mine.