Activity Vocabulary has tables which indicate several aspects (meta-properties?) of each property defined in Activity Streams 2.0. These aspects include:
- functional — is it single-value, or not?
- range — indicates the type of value the property term can have
- subproperty of — meaning that the term is a specialization of the referenced term
Here's a good example.
I haven't been able to find something like this for the properties added by ActivityPub.
For example, take following. The ActivityPub Recommendation says:
A link to an [ActivityStreams] collection of the actors that this actor is following; see 5.4 Following Collection
...
Every actor SHOULD have a following collection. This is a list of everybody that the actor has followed, added as a side effect. The following collection MUST be either an OrderedCollection or a Collection and MAY be filtered on privileges of an authenticated user or as appropriate when no authentication is given.
And that's just about it. Based on the above, I would have thought the range was Collection (like it is for replies), but looking at the examples and data returned by a Mastodon instance, I see the following property being set like this:
"following": "https://example.org/users/johndoe/following",
So what's the correct range for the following property?
Also, can an Object have multiple values for following, or is it "functional"?
In general, where are these aspects of all of the ActivityPub properties defined?