Rated 3 out of 5 stars

per Malkhasy el jul. 20, 2023 ·

The Add-on is very usefull. But, sadly, it does not work with Thunderbird 115, aka Supernova.

per Toshi (desenvolupador) a jul. 20, 2023 ·

See below.

https://addons.thunderbird.net/thunderbird/addon/display-mail-user-agent-t/reviews/1171756/

It is working fine, so please review your environment and settings.
https://i.imgur.com/wVDFI5A.png