code: public static List<Descriptor<RepositoryBrowser<?>>> filter(Class<? extends RepositoryBrowser> t) {
          List<Descriptor<RepositoryBrowser<?>>> r = new ArrayList<>();
          for (Descriptor<RepositoryBrowser<?>> d : RepositoryBrowser.all())
              if(d.isSubTypeOf(t))
                  r.add(d);
          return r;
      }
docs: Only returns those {@link RepositoryBrowser} descriptors that extend from the given type.