Thank you very much for the quick and helpful reply. Good hint that I could look in the MainUI, I try to remember that. The most helpful sources for me were the Semantic Model setup thread, the linked list of properties, locations, etc. and the Design Specs of the Location Semantic Cards.
I’d love to stop using the config files but as long as there is no simple solution to the OpenHAB configuration backup challenge in the UI, I have no other option. I have everything, the whole semantic model, things, items, rules, persistence, etc. in the text files. It’s the only way known to me how I can easily rebuild the same working OpenHAB system with a fresh install if necessary. Had in the past issues with corrupted installations where not even a file system backup (which I also have in addition) helped with restoring a stable state. Such corruption often happened much earlier and you only realize too late, and there is no backup any more without any corruption, besides the challenge that you would not know when the initial corruption happened.
I still dream of a “Backup” button in the MainUI that saves the whole configuration, i.e. the OpenHAB base config (like timzone, etc.) plus everything you configure (semantic model, things, items, rules, services, persistence, list of add-ons, etc) in a file. Once you have that file, you would be able to do a fresh OpenHAB install, and then use a “Restore” button where you specify that backup file, and a few minutes later everything is up and running again exactly as it was before. I know, there are a lot of threads out there about it and it seems to be a sensitive and emotional topic. No need to discuss it here, just explaining why I still use those text files 
Thanks again for your help, it is much appreciated!