Maintainers for kwin-x11 are Debian Qt/KDE Maintainers <[email protected]>.
You may want to refer to the following packages that are part of the same source: kwin-common, kwin-data, kwin-dev, kwin-wayland, kwin-wayland-backend-drm, kwin-wayland-backend-fbdev, kwin-wayland-backend-virtual, kwin-wayland-backend-wayland, kwin-wayland-backend-x11, libkwin4-effect-builtins1, libkwin6, libkwineffects11, libkwineffects12a, libkwineffects14, libkwinglutils11, libkwinglutils12, libkwinglutils14, libkwinxrenderutils11, libkwinxrenderutils12.
You might like to refer to the kwin-x11 package page, to the Package Tracking System, or to the source package src:kwin's bug page.
If you find a bug not listed here, please report it.