Performance wasn't really the issue here though. The issue was that Swift's C++ interop is still half-baked and kept breaking the build. You can write a perfectly fast browser in Swift for the non-hot-path stuff, which is most of a browser. They killed it because the tooling wasn't ready, not because the language is slow.

It wasn't the reason why it was removed, but, well we agree, it would have been a problem if used indiscriminately. I didn't do any additional research, but what I read in public was simply "Ladybird is going to use Swift".