an index-card is a metadata record about a specific thing.

that thing is called the "focus" of the index-card and is identified by a "focus IRI" -- any thing may be identified by multiple iris, but choose one within an index-card (and perhaps include the others with owl:sameAs)

the metadata about the thing is a quoted rdf graph in which every triple is reachable from the card's focus IRI following predicates as directed edges from subject to object.

there is not (yet) any size limit for an index-card's metadata, but it is intended to be small enough for an old computer to use naively, all at once (let's start the conversation at 4 KiB -- might be nice to fit in one page of memory)

jsonapi representation

the index-card's resourceMetadata property contains a quoted graph, independent of the rest of the response.

when represented as application/vnd.api+json (jsonapi), the resourceMetadata attribute contains a json object that has:

• @id with the focus IRI
• @type with the focus resource's rdf:type
• property keys from OSFMAP shorthand (each corresponding to an IRI)
• property values as lists of objects:
  • literal text as {"@value": "..."}
  • IRI references as {"@id": "..."}