Rated 5 out of 5 stars

A wonderful extension.

It would be nice if the 'For' field could optionally display the real recipient instead of 'Yourself' (terms translated from the French version), as there may be more than one user using TB.

This review is for a previous version of the add-on (1.1.7). 

There is an extra extension for this:
https://addons.mozilla.org/thunderbird/addon/54317

You could also turn it off by Tools->Options->Advanced->Reading&Display: Turn off "Show only display name for people in my address book".