A window manager is a piece of system software within Xorg which controls the placement of windows within a Graphical User Interface (GUI). They control serveral features of the GUI such as the borders, title bar, size and the ability to resize the windows. They can be provided as a part of Desktop Environment (Such as Kwin in KDE Plasma) with features such as icons and toolbars and the ability to provide a more consistent User Interface (UI) or they can be standalone (Such as i3) to give the user the ability to create a more lightweight and customised environment at the cost of requiring the user to add the desired software. There are 3 main types of window managers, #Stacking (Or floating) which provides the traditional desktop expereince such as Xfwm in Xfce, #Tiling where the apps 'tile' so none overlap often with minimal or no reliance on the mouse such as AwesomeWM and #Dynamic which can switch between stacking and tiling window layouts such as Dwm. Whilst on X the functionality of the window manager and Display Server are seperate on Wayland there are both combined into the Wayland Compositor.