I revisited secushareBox (AKA boxen), built it from source and tried to experiment with it.
Sadly it didn’t want to print out any logs. Which is a problem, considering it was just silently failing. After improving the logging mechanism (logging into a file is no good if the user doesn’t know about the file!) I successfully went through the device initialization and installed the service onto my PinePhone.
Right after that I looked around the code some more and found out that there is nothing more. The tool is in a VERY early stage and all it does is the VPN service initialization. You’re on your own when it comes to actually using the service.
I’m considering making this my GNUnet homework, i.e. to extend this tool and make it somewhat usable. Meanwhile, here is my secushare-box repository with the improved logging.