A Collection can e.g. come from a wikidata SPARQL result or a wiki lists or e.g. our Service Actors.
It will all boil down to 1 Link.
As an example (see Client To Server and the Conformance Section of AP), the client taxiteam can organise all the Places from wikidata in an administrative-hierarchical Collection.
But any Place with a location has a geohash in our db too
[let's stick to example Hamburg in all following text].
This means, the Place can link to e.g. their (physical) children [enhanced with OSM down to buildings], parents,
contains, neighbours, neighbourhood, siblings, findNearestAddress, findNearbyWikipedia etc.
So if {"items": ["Q1055"]} is in the Collection of "Q183" (as federal state), the same id can occur in the items for e.g.
neighbours of Q3928. The Object lives independently and so does their Activities.
If the 'Place' is also an Actor (see below), these links and rels are in streams, otherwise in url.
Basic extensibility is defined in the same spec.
4/10