Rated 5 out of 5 stars

EDIT 26.01.2022:

Thank you for your Info, rsjtdrjgfuzkfg!
I was not aware of the option to miminize to tray within the TB options. A combination of your addon with the option make my TB dream come true! <3 Of course you get 5 Stars for this now! :)

ORIGINAL COMMENT 25.06.2022:

Minimizes only to the taskbar, not to tray. :/
(WIN10, TB 91.5.1, 32-Bit)

This review is for a previous version of the add-on (2.0.1.1). 

Please read the description, this add-on is not claiming or intending to minimize to the tray. If you want that, enable minimizing to tray in Thunderbird's settings.