Please clarify the level of ES5/ES6 supported

[ngocdaothanh]

The README and the homepage don't clearly say about the level of ES5/ES6 supported:
https://github.com/metaes/metaes/blob/master/README.md
http://metaes.org/index.html

The README doesn't say anything, and the homepage only briefly says:

It doesn't implement full spec yet...
In case of MetaES those features are available in every ECMAScript 5.1+ interpreter, for example...

Please clarify more, for example what compatibility tests have passed, what tests have not passed, the roadmap/intention of the author in the future etc.

[iptop]

The implementation of callcc seems to be only toy level at present

[bartosz-k]

@iptop any examples of better than toy level implementations?

[iptop]

@bartosz-k This may be the only call / cc implementation in the current JavaScript language,But it's very different from that in scheme