Using Python and SGQLC with Shopify’s latest API (2025-01):

$ python3 -m sgqlc.introspection https://<subdomain>.myshopify.com/admin/api/2025-01/graphql.json -H "X-Shopify-Access-Token: <secret>"

{
  "data": {
    "__schema": {
      "directives": [
        {
          "args": [
            {
              "defaultValue": "null",
...

Incidentally, Shopify’s Python client establishes the schema’s URL here:

https://github.com/Shopify/shopify_python_api/blob/f58c9910e5699fbce950766772c6ac30634f85ea/shopify/resources/graphql.py#L9