There are times when I want to review my source data for importing charges, credits, payments. It would be great to be able to add attachments to the "Add to group" workflow either during the workflow of add to group OR in Process History in either (or both) the Results or Drafts tab.
Another option which would be useful but not as impactful as being able to add attachments would be for the product to retain the import file and automatically attach it to the process history log. This would be useful in sending the attachment to a colleague to show that transactions (and which ones) were imported.
These two options would remove the need to archive import & supporting data from local storage.