Install kwin by entering the following commands in the terminal:
sudo apt update sudo apt install kwin
Description:
Transitional dummy for kwin-x11
This package is a transitional dummy to depend on the renamed kwin-x11 and can be removed.
Homepage: https://projects.kde.org/projects/kde/workspace/kwin
Version: 4:5.12.4-0ubuntu2
Section: universe/utils