Where does deja-dup log its errors?

I configured Deja-dup to make a daily backup of my whole data drive. Now I get an error message each time, telling me, that not all files could be backuped. But i cannot find any Deja-dup logs in /var/log nor in the syslog. Where does it display the missing files?

Solution 1:

It seems that it doesn't really save them anywhere, but if you run it with the environment variable DEJA_DUP_DEBUG=1 you can get all the information that way.

Source: https://answers.launchpad.net/deja-dup/+question/125731

Solution 2:

In Deja-Dup on Ubuntu 16.04 (default Backup app installation), there are limited log files in ~/.cache/deja-dup/. It looks like only fairly basic information is stored by default.