`_post_dispatch` is a late addition to the httpocalypse. It can be used to alter the response object e.g. to inject headers or cookies. The function is automatically called for regular, fallback and error responses. On the other hand, `_dispatch` is only called when an endpoint is matched and might not return a response in case of error. task-2839031 closes odoo/odoo#96651 Related: odoo/upgrade#3710 Signed-off-by: Julien Castiaux <juc@odoo.com>