@id is the identifier of an entity in JSON-LD — a URL-shaped string such as https://yourdomain/#org — so that the same entity can be referenced from many places instead of restated.
Entities without @id links are fragments; with them, the Organization, the WebSite and every page's publisher are one linked graph an engine can merge.
In the JSON-LD, the Organization's "@id" and the "publisher": {"@id": …} references pointing at it.
Checked by Reflexa: Are your schema entities linked into one graph? — part of the 23 checks on every page check.
@id is the identifier of an entity in JSON-LD — a URL-shaped string such as https://yourdomain/#org — so that the same entity can be referenced from many places instead of restated.
Entities without @id links are fragments; with them, the Organization, the WebSite and every page's publisher are one linked graph an engine can merge.
In the JSON-LD, the Organization's "@id" and the "publisher": {"@id": …} references pointing at it.
The free page check runs the 23 checks on your public pages — the terms on this page, observed on your pages.