docs: public synchronized void addDeployedExtension(ModuleIdentifier identifier, ExtensionInfo extensionInfo) {
          final ExtensionJar extensionJar = new ExtensionJar(identifier, extensionInfo);
          Set<ExtensionJar> jars = this.extensions.get(extensionInfo.getName());
          if (jars == null) {
              this.extensions.put(extensionInfo.getName(), jars = new HashSet<ExtensionJar>());
          }
          jars.add(extensionJar);
      }