I also wonder how much of a pain it would be to add comments to json, like a json v2
In fact they're so easy they were already in JSON, and then later removed.
> I removed comments from JSON because I saw people were using them to hold parsing directives, a practice which would have destroyed interoperability. ~Douglas Crockford
However I think it goes too far. E.g. why support single quoted strings? That just makes parsing harder.
I prefer the format Microsoft uses in VSCode and Typescript - JSONC. It's just JSON but with trailing commas and comments. The downside is it isn't obvious when something is JSON and when it is JSONC because they use the same extension.
And something that a lot of language designs ignore: it makes writing harder and unnecessarily contentious. People will use them inconsistently, which has the usual effects any inconsistency has on cognitive load: causes others to question why/how/where.