index.yaml files that grow large in size can use significant resources to parse. Some time ago I produced some benchmarks at https://github.com/mattfarina/yamlbench. This project was originally showcased by some at jFrog at the first helm summit.

As a feature addition, we could add an index.json file alongside the YAML file. JSON uses significantly fewer resources when being parsed. For older helm clients the index.yaml would still exist. Helm could check for the json file. If not present fall back to the index.yaml file. This would enable helm to work with older repositories.

This could go into both Helm v3 and v2.