Missing icon in task switcher for Fedora KDE
App icon missing *only* in task switcher for Fedora KDE.
Setting kwin rule fixed the issue(https://discussion.fedoraproject.org/t/whats-with-the-wayland-icons-and-associated-apathy/40180/5), but should be fixed upstream.
Many other GTK apps running on Wayland have been reported to show this "Generic Wayland Icon" symptom. Unfortunately I'm not a developer but from what I can gather it seems to have something to do with xdg? Perhaps this is relevant? https://community.kde.org/Guidelines_and_HOWTOs/Wayland_Porting_Notes#Application_Icon
Setting kwin rule fixed the issue(https://discussion.fedoraproject.org/t/whats-with-the-wayland-icons-and-associated-apathy/40180/5), but should be fixed upstream.
Many other GTK apps running on Wayland have been reported to show this "Generic Wayland Icon" symptom. Unfortunately I'm not a developer but from what I can gather it seems to have something to do with xdg? Perhaps this is relevant? https://community.kde.org/Guidelines_and_HOWTOs/Wayland_Porting_Notes#Application_Icon
Upgrade Storage
For those who want to fix it manually in the meantime, the steps to follow are (adapted from the link posted by the OP):
1. Open Zotero
2. Add new kwin rule with Alt+F3 → More Actions → Configure Special Application Settings → Add Property → Desktop file name →
3. Enter "zotero.desktop" in the relevant text entry space
This works in Fedora KDE and I can't see why it wouldn't work in other KDE systems.