Rated 3 out of 5 stars
Doesn't seem to do anything (TB 60.6.1 on macOS 10.14.4)
EDIT: to be more precise, this add-on conflicts with the Display Mail User Agent extension for Thunderbird. When that is installed, Autocopy doesn't work.
Updating my rating to 3.
Sorry, but I just repacked and upload here the old extension with a little mod stated from here http://forums.mozillazine.org/viewtopic.php?f=39&amp;amp;t=3041270&amp;amp;start=90
Beyond that I don't have the skill to fix that or anything else. This addon is going to stop on the next big version of TB unfortunately.