Once I was looking through Google Drive API docs and I have seen a picture of Google Drive UI and a sidebar on the right, I guess it allowed to edit custom file properties. I need to let the user add some data to a file (like an email), so I could get it with Java SDK later.
Is it possible to edit custom properties right in Google Drive UI or that was my fantasy? Can you point out to a guide? Perhaps, it involves Google App Script or something.