GCS bucket to Looker studio custom community viz does not connect

First time trying anything like this

I want to create a custom viz in Looker Studio with d3.js

I have created a bucket d3js-bucket I have made the bucket public.

IAM has

Organization Administrator
Owner
Storage Object Admin
Storage Object Creator 

I uploaded a manifest.json and an index.js Both are public

manifest

{
  "name": "D3 Force-Directed Graph",
  "organization": "My Organization",
  "description": "A filterable D3.js force-directed graph for Looker Studio.",
  "devMode": true,
  "components": [
    {
      "id": "d3ForceGraph",
      "name": "D3 Force Graph",
      "description": "An interactive, filterable network graph.",
      "resource": {
        "js":"https://d3js-bucket.storage.googleapis.com/index.js"
      }
    }
  ],
  "interactions": [
    {
      "id": "filter",
      "supportedActions": ["FILTER"]
    }
  ]
}

I have attached a cors.json and applied it gsutil cors set cors.json gs://d3js-bucket

and verified it gsutil cors get gs://d3js-bucket

cat > cors.json <<EOF
[
  {
    "origin": ["https://lookerstudio.google.com"],
    "method": ["GET","HEAD"],
    "maxAgeSeconds": 3600
  }
]
EOF

This gives 200, so it should be accessible

curl -I -H "Origin: https://lookerstudio.google.com" \ https://d3js-bucket.storage.googleapis.com/index.js

Both manifest and index show in browser https://storage.googleapis.com/d3js-bucket/index.js https://storage.googleapis.com/d3js-bucket/manifest.json

But nothing works in Looker Studio

This gives gs://d3js-bucket/manifest.json An error occurred while requesting the visualization manifest.

This gives `Please enter a valid manifest path.

https://storage.googleapis.com/d3js-bucket/manifest.json

Note: I am not asking if my index will work properly. I am asking what needs to happen to connect.

Any ideas on what is required? or where or how to get more info on what I need to do

Thanks

According to the following codelab, the path used in the manifest should be the gs:// instead of the https:// path. It worked for me.

https://codelabs.developers.google.com/codelabs/community-visualization/#0