**Problem**
On 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 a collection of embedded entity ids on a page organized by //slot//. It should look at each //slot// to determine if any are wikibase entities and return the id for that entity. The API should **not** return related entities (i.e. on Lexemes) since those can be retrieved on the entity endpoints. Slots that are not wikibase entities should not be included in the collection.
**Example**
```
lang=json
{
"wbentity": {
"mediainfo": "M59928"
}
}
```
Alternatively, it could go in the revision object under slots:
```
lang=json
"revisions": [
{
"revid": 105192,
"parentid": 105190,
"minor": false,
"timestamp": "2018-10-30T16:08:57Z",
"slots": {
"main": {
"contentmodel": "wikitext",
},
"mediainfo": {
"contentmodel": "wikibase-mediainfo",
"wbentityid": "M59928",
}
},
}
]
```