I see easy-menu-define accepts :label for the menu name, ie. the button
which opens the menu or sub-menu.  Eg. a top-level item changing on
every redisplay,

    (easy-menu-define my-menu global-map "my menu docstring"
      '("MyTest"
        :label (format "MyTest-%d" (random 100))
        ["Foo" doctor t]))

Is this a documented feature?  It'd be good to describe it in the
docstring.  Perhaps something like below, with :help similarly too.

2014-09-09  Kevin Ryde  <user42_kevin@yahoo.com.au>

	* emacs-lisp/easymenu.el (easy-menu-define): Docstring :label and
	:help of the menu itself.