http://metadataregistry.org/uri/profile/rdakit and subelements return 404 errors

[CosmicDuctTape]

I was playing around with the Registry/Vocabulary data in Open Refine with an RDF extension, when I realized that I couldn't set http://metadataregistry.org/uri/profile/rdakit as a namespace. Trying to follow the URI in a browser or load it in elsewhere return 404 errors. I have had the same issue when trying to use the URIs for toolkitLabel, toolkitDefinition, and hasM21.