In the web interface, I can ask to see the "previous versions" and that listing tells who uploaded the file from what machine, for each version (in the last 30 days).
But that is extremely cumbersome to do for a large collection of files. What would be useful is a way to obtain the information in a single list or spreadsheet, for all the current files. If previous versions are also included, I'm OK with that too, but current version information is really what I am after.