Could you find me some deeper studies comparing JSON and HJSON? Are there any other "JSON which can be used by humans" alternatives?
It appears that formal, "deeper studies" in the academic sense (like peer-reviewed research papers) specifically comparing JSON and HJSON are rare. However, the design rationales, feature breakdowns, and formal specifications serve as the most detailed comparisons available.
Here is a synthesis of the key differences and an overview of other "human-friendly JSON" alternatives.