cron.php in core/cron.php
Handles incoming requests to fire off regularly-scheduled tasks (cron jobs).
drupal_access_denied in core/includes/
Delivers an "access denied" error to the browser.
file_download in core/includes/
Page callback: Handles private file transfers.
page_example_arguments in modules/examples/page_example/page_example.module
A more complex page callback that takes arguments.
system_batch_page in core/modules/system/
Default page callback for batches.
system_date_delete_format_form in core/modules/system/
Menu callback; present a form for deleting a date format.
user_pass_reset in core/modules/user/
Menu callback; process one time login link and redirects to the user page on success.
views_plugin_display_page::execute in core/modules/views/plugins/
The display page handler returns a normal view, but it also does a backdrop_set_title for the page, and does a views_set_page_view on the view.