What probably matters to youSection of the release
What
Creating an Artifact from a type can now pass auto_open: "after_first_write", which holds back opening it for you until content actually lands, so you no longer watch an empty page. The pending open is parked per Artifact and flushed by the first successful write, or consumed by a later publish of files. Validation rejects the value when there is nothing to wait for, such as a publish that is itself the first write.
Details
The alternative value is at_create, the previous behaviour of opening immediately.
No separate flag for auto_open was found; it rides on the existing Artifact type-creation schema.
Evidence
after_first_write
Strings lifted out of the shipped bundle, so the claim above can be checked against them.