but it's not like AS2 didn't think of this. they wrote in this requirement: https://www.w3.org/TR/activitystreams-core/#extensibility
> Activity Streams 2.0 implementations that wish to fully support extensions MUST support Compact URI expansion as defined by the JSON-LD specification.
note, you aren't required to implement all of json-ld. you just need to handle the bit where you can identify the equivalence between a uri and some arbitrary string.
but #fediverse mostly decided this is too hard, and ignore context.
21/?