It would be entirely possible to generate a JSON-LD context object from an RDFLib `DefinedNamespace` or `ClosedNamespace`. An example of an existing context and `DefinedNamespace` is available for GeoSPARQL: * [OGC's geo-context.json](https://raw.githubusercontent.com/opengeospatial/ogc-geosparql/master/1.1/contexts/geo-context.json) * [DefinedNamespace in RDFLib source code](https://github.com/RDFLib/rdflib/blob/master/rdflib/namespace/_GEO.py)