How do I remove 19GB of mystery "Documents" from iCloud
I have iCloud to sync Calendar and Photos. However, I do not have iCloud drive, and no documents at all stored in iCloud. Or so I though, until I started getting messages about my 50GB storage almost being full. When I check the manage storage (on the mac or web) I can see that I have ca 5GB of Backups, 20GB of Photos and apparently 19GB of "Documents".
What are these documents? And how can I get rid of them so that I can reclaim the space? I don't have and never have had iCloud drive, so I can't access that to see or remove any files.
Mac Pro, macOS Sierra (10.12.6)