The files under https://ontology.bonsai.uno/core/
are
ontology_v0.1.rdf
ontology_v0.1.ttl
ontology_v0.2.rdf
ontology_v0.2.ttl
Maybe if we request
https://ontology.bonsai.uno/core/ontology.ttl
we should point to the latest ontology_v0.2.ttl instead of 404