Perhaps also a running log.
Hello @lowspeed, welcome to the Forum! 
The reports that can be emailed upon completion of a backup job include this information. Relevant fields include:
- deleted files
- modified files
- examined files
- opened files
- added files
There are a lot of other fields. The one most directly related to your question would be either Opened Files or Examined Files (they’re typically the same number).
I’m not sure how to extract the log from a backup after a run. Perhaps one of the Duplicati experts (which I am not) can answer this. The log can be viewed in real time during the backup through the GUI.
Viewing the log files of a backup job shows how to get to some of the logs. It’s not on the home screen, however the newer versions give a good summary – plus the old harder to read log file if you want that:
