There are two mixins that will contribute to this interface:

Either of these can be suppressed, if required, using a vetoing subscriber that listens to the action or property domain event in order to hide the member.

For example, a Customer object with an logical type name of "custmgmt.Customer" and an id of 123 would correspond to a Bookmark with a string representation of "custmgmt.Customer|123".

Bookmarks are useful to store a reference to an arbitrary object, although be aware that there is no referential integrity.

Several of the extension libraries use bookmarks. For example the EntityPropertyChangeSubscriber uses bookmarks to identify the object that is being modified.

Serialized form of bookmarks also appear within schema instances, for example as used by CommandSubscriber and the ExecutionSubscriber.