**Problem**
A page response object like this:
https://www.wikidata.org/w/api.php?action=query&format=json&prop=info&titles=Q2&formatversion=2
the entitiy id is obvious as it's the same as the `title`.
This response is slightly more complicated
https://www.wikidata.org/w/api.php?action=query&format=json&prop=info&titles=Property%3AP18&formatversion=2
however, it's easy to determine the entity id (the title, sans namespace)
However, a request like this:
https://commons.wikimedia.beta.wmflabs.org/w/api.php?action=query&format=json&prop=info&titles=File%3ARedsq.png&formatversion=2
it can be impossible to know that the entity id is `M59928`
**Solution**
Wikibase should add a new property to the page response object that will return an array of embedded entity ids on a page. It should look at each //slot// to determine if any are wikibase entities and return the ids for those entities. The API should **not** return related entities (i.e. on Lexemes) since those can be retrieved on the entity endpoints.