<private> means it's not allowed to log details for privacy reasons.
Try running:
Code:
sudo log config
It probably won't include PRIVATE_DATA. If so, run this:
Code:
sudo log config --mode "private_data:on"
Then run the original command again. (In my case, it first said "System mode = INFO DEBUG STREAM_LIVE", then "System mode = INFO DEBUG STREAM_LIVE PRIVATE_DATA".)
This isn't persisted across reboots, I believe. But it should be enough to gather some more information on what Spotlight is trying to index.