Custom meta model plugin in camunda modeler

I am looking to load the as a plugin in my camunda modeler.

I have added the index.js file which loads the bundled file as the script and included the plugin directory under ~/Library/Application Support on macOS/camunda-modeler/plugins
but I don’t see this plugin code loaded on inspecting camunda modeler.

I see other plugins which are plugins on modeler which do not extend the xml or palette working. What am I missing here? Is it possible to add this as a plugin at all?

module.exports = {
  name: 'Custom meta model',
  script: './dist/index.js'

Is using bpmn extension element ( as a plugin in camunda modeler correct at all?
Appreciate any help on this question.

Make sure to add the custom meta model as a model extension:

import {
} from 'camunda-modeler-plugin-helpers';

var moddleDescriptor = {
  name: 'my descriptor',
  uri: '',
  prefix: 'mydesc',