aggregator_menu in modules/aggregator/aggregator.module
Implementation of hook_menu().
menu_menu in modules/menu/menu.module
Implementation of hook_menu().
statistics_menu in modules/statistics/statistics.module
Implementation of hook_menu().
user_menu in modules/user/user.module
Implementation of hook_menu().
_menu_check_access in includes/menu.inc
Check access to a menu item using the access callback
_menu_router_build in includes/menu.inc
Helper function to build the router table based on the data from hook_menu.