This is the important part. The message had an envelope-recipient of "email@example.com" (please don't use domains like "mydomain.com" as examples, unless you actually own that domain).
See https://panel.dreamhost.com/kbase/index.cgi?area=2704 for a somewhat lengthy explanation of why it shows up this way.
This is easy to do. The "To: " header doesn't have to bear any relation to the address(es) a message is sent to - it is just a component of the message body. If you're having sendmail read the recipients from the message headers, /then/ it's important, but it's trivial to do:
The relevant bits of the SMTP transaction would look something like:
Subject: This is a fake message
[rest of headers and body]