Rated 4 out of 5 stars

I'm using the TT Deepdark theme and when I installed this extension I lost my Reply-all button. Uninstalling this brought the button back. That said, this extension seemed to do what it was intended and I was using it to load a pre-built html file as a template for an email, which it did very nicely. Using Thunderbird 52.6

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