[zeroimpl]

Example? I know there's some ambiguity over whether literals like false are valid JSON, but I can't think of anything else.

[tubthumper8]

That _shouldn't_ be ambiguous, `false` is a valid JSON document according to specification, but not all parsers are compliant.

There's some interesting examples of ambiguities here: https://seriot.ch/projects/parsing_json.html

[recursive]

Trailing commas, comments, duplicate key names, for a few examples.

[int_19h]

Trailing commas and comments are plainly not standard JSON under any definition. There are standards that include them which extend JSON, sure, but I'm not aware of any JSON library that emits this kind of stuff by default.