#12245 added the ability to work with index.json files. But, there are two problems with it that need to be worked out.

1. Helm does not have a method to read the created index.json files. It assumes the extension is .yaml when autodiscovering.
2. If Helm 3.13.0+ creates an index.json file, what is the story for older versions of Helm that do not know to look for the index.json file? Is this a new opt-in feature all the way around?

cc @joejulian @sabre1041

Output of helm version: 3.13.0

Output of kubectl version: N/A

Cloud Provider/Platform (AKS, GKE, Minikube etc.): N/A