Thundbird: Size Matters
For an aging Gen Xer like me, font size starts to matter, especially on a 4K display. So being able to change the font size in case the app can’t scale automatically on high dpi screens is a must.
In case of Mozillas Thunderbird, this is way more complicated then necessary and not very well documented. So I added my Gitlab repository for my reference – and maybe it will help you as well. Just put it in to your ~/.thunderbird/<*>.default-release/chrome directory and everything will get bigger ;)