Rated 5 out of 5 stars

I subscribe to the 'voice message to email' service that my phone carrier provides, and filter and save these emails into a special folder. When the email arrives it has a subject line like: 'call from xxxxxxxxxx'(10 digit phone #) or 'call from an unknown sender' or 'call from a private-user'
With Header Tools Lite, I can rewrite the subject line to provide more pertinent detail. 'call from Mike's cell' rather than 'call from a private user'. I also like the idea that none of the other details are changed (unless I want.)

My only problem is with the security aspect. If I ever have to produce a saved email for a legal purpose, It may not be accepted, When you compare the sender's copy with the recipient's, they will not correspond, and then the whole document may be discounted. (Courts are funny that way!).

Legal issues aside, I found that this extension works fine, right out of the box, on Thunderbird 17.0
Good job! (4.5 stars)

This review is for a previous version of the add-on (0.4.4).