Until now, you haven't been able to delete files that are part of a multi-file field.
Now all you have to do it open the preview and confirm that you want to delete the chosen file. This is great if you've uploaded the wrong file, need to replace a file or any other reason why you might need to delete a file.
Another improvement to our csv import functionality! When importing a CSV you can now download a template with the expected headers. This should make it easier to populate the expected fields and help avoid any manually mapping of columns to fields - it’ll be picked up automatically!