4 invocations of hook_exit()

ajax_footer in includes/ajax.inc: Performs end-of-Ajax-request tasks.
drupal_exit in includes/common.inc: Performs end-of-request tasks.
drupal_page_footer in includes/common.inc: Performs end-of-request tasks.
_drupal_bootstrap_page_cache in includes/bootstrap.inc: Attempts to serve a page from the cache.

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