I use comcast for my email and receive all mail directly to the mail program on my mac. The problem is that there is no Time Machine Folder on the column you are mentioning and I have to go through this obscure processto find the recovered mail with a smart folder in mail
As previously mentioned it is in a hidden folder com.apple.mail.backingup.mbox. which can't be made visible on the mail sidebar.or I can find it by making it visible in the mailbox folder in user/library /preferences. I and Apple at the moment can't make it visible on the sidebar of mail under on my mac.
Thanks Mark