The last post by Arne in BugZilla brings me to the question:
Which files shall be saved and which not?

The script  /var/ipfire/backup/bin/backup.pl together with the configs include and exclude do NOT the job intendeded, as I interpret it, at  the moment.

Surprisingly nobody complaint so far. I think the usual handing by the users was and is: backup-->restore-->rebuild info that is missing.
But the last step shoukdn't be necessary!

Bernhard