Where fetchmail stored read mail

By default, fetchmail stores read mail in the Maildir format, which is a popular mail storage format that is widely used by many mail clients and servers.

When fetchmail retrieves new mail from a mail server, it stores the new mail in a directory called Maildir (or Maildir/ if the directory is not specified). Within this directory, fetchmail creates three subdirectories:

1. new: This directory contains new, unread mail.
2. cur: This directory contains the actual mail messages, which are stored in a format called mboxrd.
3. tmp: This directory is used temporarily to store mail messages while they are being processed.

When you use a mail client to read mail, it typically moves the mail from the new directory to the cur directory, marking it as read. The cur directory is where fetchmail stores the actual mail messages, and it's where your mail client will look for new mail.

Here's an example of what the Maildir directory structure might look like:

Maildir/
new/
1234567890.M
1234567890.S
cur/
1234567890.M
1234567890.S
tmp/

In this example, the new directory contains two new, unread mail messages (1234567890.M and 1234567890.S). The cur directory contains the same two mail messages, but they are marked as read. The tmp directory is empty.

Note that the Maildir format is highly flexible and can be customized to suit your needs. You can change the directory structure, add additional directories, or modify the way mail is stored and retrieved.