Hjson, the Human JSON · shard-db HN Explorer

So it's basically like YAML, except it has libraries only for a handful of languages and nobody uses it.

Except that a valid JSON is a valid Hjson as well.

So, you mean a valid JSON is not a valid YAML? Good that YAML doesn't know that, otherwise my libraries start to reject JSONs.

Hjson, the Human JSON (hjson.org)