(I find it weird that this file would be in /lib/, the usual location is /etc/, but apparently the package does refer to /lib/ and that should work … but still sounds like a weirdness directly in the package)
Thank you very much for your help, but I think my problem got much worse …
I listed the files as you suggested and started to write my answer. After a while I noticed that I could not reach some folders any more. Then the webinterface delivered a nginx error.
I tried to connect with ssh, but all password entries failed with all users I know.
Finally I had to pull power supply. Now the Raspberry isn’t booting any more.
Seems like I broke my second SD card in one week