This is exactly what I was hoping to find... something that can, in one fell swoop, delete all email addresses in the To, CC or BCC rows when I use “Edit as New” for an email I've previously sent to many recipients but where I want to remove their addresses. Without this extension, Thunderbird will only let you delete recipient email addresses one by one... if there are a lot of them, this is a tortuous time-consuming effort. With this extension, just click the button and, poof, they’ve all gone in one go! Brilliant!
[Using TB 38.6 on Mac OS X 10.10, with tons of other extensions]
This review is for a previous version of the add-on (1.2).