A policy allowing delivery of cached pages when there is no session open.
Do not serve cached pages to authenticated users, or to anonymous users when $_SESSION is non-empty. $_SESSION may contain status messages from a form submission, the contents of a shopping cart, or other userspecific content that should not be cached and displayed to other users.
Hierarchy
class \Drupal\Core\PageCache\RequestPolicy\NoSessionOpen implements RequestPolicyInterface
File
core/lib/Drupal/Core/PageCache/Req