Add Wayland support to Thunderbird. This is especially important for HiDPI screens on Wayland, because the Thunderbird UI is huge on these screens.
Apparently, there is already a thunderbird-wayland package.
Yes, see my blog https://mastransky.wordpress.com/2019/02/08/thunderbird-for-wayland/
Upstream TB is going to have Wayland support when it's based on Firefox 68 ESR release.