"none":
No authentication
Compatibility note: Thunderbird 3.0 accepts only "plain" and "secure". It will ignore the whole XML file, if other values are given.
<pop3>
<!-- remove the following and leave to client/user? -->
authenticate to incoming mail server first
before contacting the smtp server.
Compatibility note: Thunderbird 3.0 accepts only "plain", "secure", "none", and "smtp-after-pop". It will ignore the whole XML file, if other values are given.
-->
<addThisServer>true</addThisServer>