I find json5 much better than json, but it has still many of the same annoyances.

- instead of trailing commas, how about making them completely optional? It's not like they are needed in the first place.

- curly braces for top-level objects could be optional too.

- For a data exchange format, there should really be a standard size for numbers, like i32 for integers and f64 for floats.

- parsing an object with duplicate keys is still undefined behavior.