Kxclib_js.Json_extJson_ext concerns the type xjv, meaning external json value.
It only makes sense on a virtual machine shared with a JavaScript runtime.
type xjv = private js_valval to_xjv : Kxclib.Json.jv -> xjvval of_xjv : xjv -> Kxclib.Json.jvval to_json_string : Kxclib.Json.jv -> stringval of_json_string_opt : string -> Kxclib.Json.jv option