Even in the first position? That makes it no longer be the claimed "superset of JSON", since (AFAIK) {"key":"value"} (with no whitespace) is valid JSON.
For delimited collections, so within {} and [], if the key is quoted, then you don't need the whitespace. So your example parses as expected as does `{"key":value}`, but `{key:value}` turns into `{"key:value": null}`.
