code: private JqassistantPlugin readPlugin(URL pluginUrl) {
          try (InputStream inputStream = new BufferedInputStream(pluginUrl.openStream())) {
              return jaxbUnmarshaller.unmarshal(inputStream);
          } catch (IOException e) {
              throw new IllegalStateException("Cannot read plugin from " + pluginUrl.toString(), e);
          }
      }
docs: Read the catalogs from an {@link URL}.
  
  @param pluginUrl The {@link URL}.
  @return The {@link JqassistantPlugin}.