Hi.
I would like to create a theme for Thunderbird.
I have noticed recent UI updates in version 78.x that makes some previous themes broken.
Furthermore current documentation on Thunderbird theming seems either outdated, not fully relevant to Thunderbird or incomplete.
Can someone at Mozilla please create a comprehensive and complete guide into how to create themes for Thunderbird, mostly concerning a full list of style classes currently used.
Kind regards,
Reece