Identifier: window_numbers
Identifier: window_numbersnumeric
Whether window numbers are to appear in window titles. When window_numbers is set to 1, titles for all new windows are prefixed by their win# index. When it is set to 0, they are not. Window titles are displayed in a cladding frame supplied by the window manager.
Window numbers can be included/excluded on a per-window basis by means of the -num switch available on all window creation commands.
At system start-up window_numbers has a value of 1.