I think the author of RDF* did initial prototype works with Jena

https://github.com/RDFstar/RDFstarTools

so I've been thinking... would be really nice to have a custom slack for RDF and related technologies

I don't think there's such thing right now

I found a mattermost for Rdf4J but it seems dead

(https://mattermost.eclipse.org/eclipse/channels/eclipse-rdf4j)

we've implemented rdf* and sparql* in Stardog