Using Web Push API with cordova phonegap-plugin-push and FCM

Question

We've a cordova app that uses push notifications which works fine on android and iOS. I now thought I'd like to test if I also get the Web Push API to work on the browser platform / as PWA.

However, I didn't manage to find any guidance how to do this.

Nearly all examples I found that have the browser platform included use the example from https://github.com/phonegap/phonegap-plugin-push/blob/master/docs/API.md#pushnotificationinitoptions

const push = PushNotification.init({
  browser: {
    pushServiceURL: 'http://push.api.phonegap.com/v1/push'
  }
});

However, the domain push.api.phonegap.com seems to be non-existent by now.

The Firebase doc I found doesn't explain how to use FCM with the push plugin that already does most of the stuff described there (I would expect).

I found an example that uses pushServiceURL: 'https://fcm.googleapis.com/fcm/send' but the question already states that "First of all, I don't know if the pushServiceURL is correct. Is this the URL to use if I'd like to send some notifications from FCM?"

And I understand https://firebase.google.com/docs/cloud-messaging/http-server-ref that this URL is the server-side API.

So, did anyone manage to use the Web Push API with the phonegap-plugin-push? With FCM or with andouter service?

Thanks!