Okular wrote:
If I want to rework and redesign my web Gallery, what will be the best way to preserve and backup the current site and build up the new one in parallel - if this is possible at all? Thanks for any helpful hints!
It's a bit unclear what you mean "build up the new one in parallel", so it's a bit hard to answer. If you want to have both old and new websites available, you could just keep separate X3 installations in subdirs /old/ and /new/ ... or just have the new one in root /.
Optionally, you could backup your /config/ and /content/ dirs as a zip file, or duplicate the two dirs as /config_bac/ and /content_bac. The /config/ and /content/ dirs are the only dirs that define your actual unique X3 website ... The other dirs and files are just application files.
If you are just going to change the global style but keep pages/galleries, you could just backup the /config/config.user.json file.
It's a bit unclear exactly what you want to do, but if you want to have both the new and old website active at the same time, you would need to use the first, option with separate X3 installations in separate dirs.