one of the documented procedures in this installation of the ACS
ad_scope_navbar   args
What it does:
if scope is not set in the topmost environment then public scope is assumed. if scope=group, it assumes that group_navbar_list is set in the topmost environment. produces navigation bar. notice that navigation bar is different than context bar, which exploits a tree structure. navbar will just display a list of nicely formatted links.
Defined in: /web/philip/tcl/ad-scope.tcl

Source code:

    if { [uplevel [ad_scope_upvar_level] {info exists scope}] } {
	upvar [ad_scope_upvar_level] scope scope
    } else {
	set scope public

    set all_args [list]
    switch $scope {
	public {
	    set all_args $args
	group {
	    upvar [ad_scope_upvar_level] group_vars_set group_vars_set
	    set group_navbar_list [ns_set get $group_vars_set group_navbar_list]

	    eval "lappend all_args $group_navbar_list"
	    foreach arg $args {
		lappend all_args $arg
	user {
	    set all_args $args
	    # this may be later modified if we allow users to customize the display of their pages	    

    return [eval "ad_navbar $all_args"]