Message Header Analyzer uses EWS and REST to retrieve the transport message headers of an e-mail message and display them to the user in an easy to read format. Now with iOS support!
When this add-in is used, it
Can send data over the Internet
This add-in can read or modify the contents of any item in your mailbox, and create new items. It can access personal information -- such as the body, subject, sender, recipients, or attachments -- in any message or calendar item. It may send this data to a third-party service.