`wm` (short for window_manager) is used for managing or finding
information about `toplevels`, while `winfo` (short for widget_info) is
for querying info about all types of widgets.
For example, `wm geometry .` will give you the size of the main
toplevel, including window manager decoration, as perceived by the
window manager. However, `winfo geometry .` returns only the size of
"." as perceived by Tk.