wm command window ?value?
If value is specified, this command stores value in window 's WM_COMMAND property for use by the window manager or session manager and returns an empty string. Value must have proper list structure; the elements should contain the words of the command used to invoke the application. If value isn't specified then the command returns the last value set in a wm command command for window. If value is specified as an empty string, the command deletes the WM_COMMAND property from window.
See also:
wm is a Tk command. It has a number of subcommands (sometimes referred to as minor commands). wm command is one of these minor commands.
I presume someone is contemplating creating a page to talk about how one uses the wm command subcommand effectively.
The wm command command is used to provide some level of compliance with the ICCCM. In order for the session manager to be able to restore an application, it must know how to start that application. The most basic way to do this is:
wm command . [linsert $argv 0 $argv0]
You should also use the wm client command to set the application client, thus:
wm client . [info hostname]