Comment by rdsubhas
Problem: Trailing commas, key-quoting-rules, etc are a problem when generating JSON from scripts/templates - which is a key practical necessity for a Configuration language. Of course, you may already disagree here and say you don't have this problem, but it's a sufficient problem for everyone that there are many attempts to solve it. If you don't have this problem, feel free to ignore.
MAML: Takes JSON, makes trailing commas & key-quoting optional. One may not like it, but it does indeed solve the scripting problem, and it's a nice and novel idea. Thereby it's a "Superset" of JSON. All JSON is valid MAML, but all MAML is not valid JSON.
JSONNet: Also a good attempt, directly solving the scripting problem with built-in functions and so on. But can be overwhelming.
Other approach: A strict "Subset" of JSON. Every value MUST end with a comma, whether it's first or last. Every key MUST be quoted. Comments MUST be a valid JSON key-value called ".comment" that will be ignored at parsing but otherwise part of the JSON. JSON5 seems to be more suitable for this.