This is the easier concept to understand. User-data-files are the files that users have uploaded to the system. They can be anything that complies with XcooBee file extensions Allowed File Extensions. For example images, contracts, proofs, spreadsheets, movies, etc.
In addition, XcooBee allows semantic and user specific tags to be added to each file via the directive files concept.
Files/Documents uploaded can be processed by the uploading user or by receiving user.