Earlier, users had to kill windows using application-supported means (e.g., typing "exit" in a terminal). Now, Minx adds a function that allows users to bind a key to kill a window.
The default key binding for this is ALT + F4 and it kills the currently focused window. However, if you so please, you can bind your own function to some key and, thereby, find a particular window to kill and kill that instead of the focused window.
Minx's window killing function uses the WM_DELETE_WINDOW protocol if the window supports it. This gives client applications an opportunity to, for example, save open files, etc. before they are shut down. However, if a window does not support WM_DELETE_WINDOW, Minx will kill it by brute force.