Binary package “xfwm4” in ubuntu mantic

window manager of the Xfce project

 This package contains xfwm4 which is the window manager for Xfce4. It is
 designed to run with the rest of Xfce4 but makes a capable window manager
 for GNOME or KDE.
 .
 Install xfwm4 if you want a small, resource saving window manager which
 complies to the standards defined at http://www.freedesktop.org/. Without
 xfce4 installed this only gives you a window manager not the full
 environment.