By default, when requesting a resource that is not within the scope of specific root resource handler, the GraphNode of that resource from the UnionContentGraph is returned (i.e. its context serialized or passed to the templating system). In some situations specific code should be executed when a resource of a certain type (according to the UnionContentGraph) is requested. For looking up with the resources in the UCG only the part of the URL before the query part is considered.
In the system graph there's a list of RDF resource types mapped to root resource classes, the path of this root resource classes is ignored as well as any non-root resource method (at least currently, ideas to look for subpath resource have been discussed).