I'm using the Kubuntu Oneiric version of kmail (kmail2?) to manage my mail. I accidentally deleted all my mail by deleting the Local Folders account. (I didn't know what the purpose of that account was.) That's not quite the disaster it might have been, since I'm using Dropbox, and Dropbox keeps complete backups of my entire Mail directory. I can restore any file to a previous state -- including deleted files.

However, Dropbox does not provide a way to restore a directory to a previous state, only to restore files -- including files in deleted directories. So I can get my mail back if I know what files I need to restore. But the Mail directory includes a great number of files, and there's no way to restore all of them in a single operation. Most of them, of course, are just fine. Which ones do I need to restore?