This service fills a gap between services like prefix.cc and LOV or looking up the original vocabulary specification. Not all vocabularies (or schema or ontology, whatever you want to call them) provide an HTML view. If you resolve some of the common prefixes all you get back is some RDF serialization which is not ideal. (from <https://prefix.zazuko.com/about>)
zazuko
frbr
https://bioregistry.io/metaregistry/zazuko/resolve/frbr
frbr:Expression
https://prefix.zazuko.com/frbr:Expression