https://gitlab.gnome.org/GNOME/evolution/-/issues/3095#note_...
1. Submit a bug report to the library and then do nothing else, for over a year, with no end in sight, and say it's not your problem, you can't fix it, and there's nothing you can do, and you wont tell your users.
2. Address the problem by fixing the library yourself, or getting somebody else to actually fix it, switch to a different library, patch over the problem on your applications side?
If number 1 is your answer, you probably shouldn't be distributing software.
I'll let Balsa and Geary know about the preconnect problem. Will be interesting to see if they take the same awful approach that Evolution Mail did to addressing it.
[edit]
I've just tested, and both fail the link preconnect test but neither fail the dns prefetch test.
So the original bug I posted is on the Evolution Mail side, not the Webkit side. If you go back and look at the thread, you'll see they never actually investigated the issue. They just insisted it wasn't their problem. They were wrong.
They locked the bug of course, because their feelings are more important than distributing secure software to them, so I have no way of informing them of this. They're just pissed they can't lock my blog and that people are finding out about this issue, outside of their control.