Expiration encodes an expiration date-time. A node that contains this metadata field should not be valid/relevant after the encoded date-time.
Expiration is designed to be somewhat atomic. It doesn't strictly rely on any other twig extensions and can be used as a building block for more complex behavior.
An example API usage would check the expiration data/date and determine if the node is expired or not:
commit bc5691fbee23d4933ced1ba734db739aad833611 Author: Chris Waldon <firstname.lastname@example.org> Date: 2021-10-27T15:59:49-04:00 content: fix self hosting guide Signed-off-by: Chris Waldon <email@example.com>