Rated 5 out of 5 stars

Very good plugin, one of the most essential I use. Unfortunately
It doesn't work with TB 78.2.2. New version is highly anticipated.
Thank you!

As my distro force-migrated me to 78.4, I had to address that issue, finally:
Please have a look at https://addons.thunderbird.net/de/thunderbird/addon/toggle-line-wrap for a successor.