A widget, script, or UDIX can read the mailbox by using Framework.RequestMail(). This will issue an immediate (asynchronous) MAILBOX message to OnMessage(), followed by further MAILBOX messages whenever there are changes in the mailbox.
A MAILBOX message has a mail[] array listing all the messages currently in the system. It always lists all messages. On receipt of new mail, the MAILBOX message will contain the entire mailbox, not just the new message.
Widgets, scripts, and UDIXes can only see user-to-user messages. They cannot see messages issued by the broker. This is because those may contain sensitive information such as account passwords.
