docs: @SuppressWarnings({"unchecked"})
      public <T> ExtensionList<T> getExtensionList(Class<T> extensionType) {
          ExtensionList<T> extensionList = extensionLists.get(extensionType);
          return extensionList != null ? extensionList : extensionLists.computeIfAbsent(extensionType, key -> ExtensionList.create(this, key));
      }