[vasilvv]

Isn't this the problem that JSON5 (and probably other similar projects) is supposed to solve?

Both JSON (as defined in the RFC) and JSON5 have a nice property of being well-defined, meaning that you can use different libraries in different languages on different platforms to parse them, and expect the same result. "JSON but parser behaves reasonably (as defined by the speaker)" does not have this property.

[donatj]

JSON5 would be ok if that's all it did. They added so much additional unnecessary complication that it undermines the simplicity of JSON that makes it good.

[avmich]

http://seriot.ch/projects/parsing_json.html

"Despite the clarifications they bring, RFC 7159 and 8259 contain several approximations and leaves many details loosely specified."

[hinkley]

Nothing will probably ever top Markdown in my mind for bullshit specifications.

And Gruber wouldn’t give Jeff Atwood permission to call his variant <something> Markdown, or it seems anybody else, so we ended up with CommonMark, and GFM.

Json5 is good for JSON at rest, as others have mentioned already.