When I had been using Duplicati for a short while, my computer crashed and I had to do a restore without any metadata. After that bad experience I decided to back up the job databases in a separate backup job.
Recently, one of my computers again crashed and I needed to perform a restore. This time, I was much more familiar with Duplicati, and knew the procedure much better. I learned that all I need is to re-create job definitions, either from a saved .json file, or just by typing in the info in the web ui. I didn’t have .json files, but I knew the job names, so I manually created my backup jobs anew, not even having the full exclude lists at hand. This I wasn’t able to do the right way back in the early days, but this time I knew exactly what to do.
Once I had done the restores I needed, I then updated the new job definitions and saved them into .json files with the export functionality. I created a separate directory for them, ~/.config/Duplicati-json, which I include in my backups, or at least in one of them. I cannot be 100% sure I remember to do the export into .json files every time I modify the job definitions, but after the latest experience, I know that the most important information to have at hands is passwords and storage locations. Once you have created some way or another a job definition that points to a storage location, you can then view what is in there and update the job’s source list and filters accordingly.
I have now dropped the separate job that backed up my ~/.config/Duplicati, as with the latest experience, I know I don’t need it.