Hi.

I have fantastic news. We are growing! 🐈 Together with this, our documentation grows and we have newer needs and requirements. 

We currently only publish documentation for our app releases. 
 - https://airflow.apache.org/docs/stable/

But our community is also working on other products that have a different release cycle, use case, docs build tool and needs
- Production Docker image: https://hub.docker.com/r/apache/airflow
- REST API: https://airflow.readthedocs.io/en/latest/stable-rest-api-ref.html (it has a separate version number, so a version index could be helpful. We can also set the version to the application version)
- Backport/provider packages: https://github.com/apache/airflow/tree/master/backport_packages
- Helm Chart: https://github.com/apache/airflow/tree/master/chart
- [API Clients for Apache Airflow](https://github.com/apache/airflow/issues/10176)
  - Go: https://github.com/apache/airflow-client-go 
  - Python: https://github.com/apache/airflow-client-python
  - Java: https://github.com/apache/airflow-client-java
  - Javascript: https://github.com/apache/airflow-client-javascript
- Apache Airflow on K8S Operator: https://github.com/apache/airflow-on-k8s-operator

and other: https://github.com/apache/airflow/issues/10550, https://github.com/apache/airflow/issues/10552

I think it is worth considering how we want to inform users about these products on our website.  

One solution is to create an index at: `https://airflow.apache.org/docs/` (currently there is a redirection to the latest stable version of the documentation), which will refer you to separate documentation for each product.
It will look similar to the examples:
https://mc-stan.org/
https://cloud.google.com/sql/docs/
https://www.terraform.io/docs/

An alternative solution is moving all documentations to our app documentation:
https://github.com/apache/airflow/pull/11136
https://github.com/apache/airflow/pull/10998

What is our plan for this documentation? Do we need to standardize our documentation building tools? What requirements does each documentation have, e.g. do we always need versioning? 
CC: @kaxil @potiuk 

docs/exts/airflow_intersphinx.py
intersphinx_timeout = None
            intersphinx_cache_limit = 1
            tls_verify = False
            user_agent = None
        class _MockApp:
            srcdir = ''
            config = _MockConfig()
            def warn(self, msg: str) -> None:
                """Display warning"""
                print(msg, file=sys.stderr)
        def fetch_inventories(intersphinx_mapping) -> Dict[str, Any]:
            now = int(time.time())
            cache: Dict[Any, Any] = {}
            with concurrent.futures.ThreadPoolExecutor() as pool:
                for name, (uri, invs) in intersphinx_mapping.values():
                    pool.submit(fetch_inventory_group, name, uri, invs, cache, _MockApp(), now)
            inv_dict = {}
            for uri, (name, now, invdata) in cache.items():
                del uri
                del now
                inv_dict[name] = invdata
            return inv_dict
        def domain_and_object_type_to_role(domain: str, object_type: str) -> str: