docs/data/reusables/notifications/shared_state.md

Tip

If you receive notifications both via email and on {% data variables.product.github %}, you can automatically sync the read or unread status of the notification so that notifications on {% data variables.product.github %} are automatically marked as read once you've read the corresponding email notification. To enable this sync, your email client must be able to view images from {% ifversion fpt or ghec %}notifications@github.com{% else %}the no-reply email address for {% data variables.location.product_location %}, which your site administrator configures{% endif %}.