Rated 5 out of 5 stars

Nice and useful add-on. Really like to see what mail system have been used to send me a message :)
The only thing I'm not 100% happy with are very large (48x48) icons indicating mail system used. It could be nice if there are smaller icons available (32x32, 24x24...) with possibility to configure the icon size (big, medium, small).

This review is for a previous version of the add-on (1.6.9).