The Adwaita Icon Theme no longer follows the FDO icon naming spec breaking KDE applications on Fedora 40 Workstation and Co. See the concrete state of the issue in the linked article.
Just a quick screenshot from Kate 24.04.80 (beta1 before 24.5.0) on Haiku, I’m not sure if Haiku respects the FDO naming spec, but atleast the icons aren’t broken so fallback to the breeze icons for the ones not present in Haiku’s icon set still seems to be fine. :)
Nice :) In my new post I did try the current KF5 Kate on Haiku, too, works. https://cullmann.io/posts/kde-applications-and-icons/