maildirs is a program that reports the existence of maildirs within a directory tree. It was written for use in configuring the Mutt mail reader with a list of mail storage locations to use.
mailcp is a simple program to copy from one mailbox to another. For example, it can move messages from an IMAPS mail store to a Maildir mail store. It uses libvmime and thus checks TLS/SSL certificates in a dependable and secure way.
A PHP framework.
A simple lock manager.