a strict superset of JSON, relaxing strictness of valilla JSON. Valid, vanilla JSON will not be changed by RJSON.transform. But there are few additional features helping writing JSON by hand.
Comments are stripped : // foo and /* bar */ →      . Comments are converted into whitespace, so your formatting is preserved.
Trailing comma is allowed : [1, 2, 3, ] → [1, 2, 3]. Works also in objects { “foo”: “bar”, } → { “foo”: “bar” }.
Identifiers are transformed into strings : { foo: bar } → { “foo”: “bar” }.
Single quoted strings are allowed : ‘say “Hello”‘ → “say “Hello””.
More different characters is supported in identifiers: foo-bar → “foo-bar”.