A new ES6 spec. draft has been posted

At the usual place: http://wiki.ecmascript.org/doku.php?id=harmony:specification_drafts 

Changes include:

Made Symbols a primitive type
Added semantics for generator function and generator method definitions
Added semantics for array comprehensions and generator comprehensions
Added semantics for yield and yield*
Replaced StopIteration exception with nextResult objects
Updated for-in/of semantics to use new generator protocol
Made Arrow function and concise method formal parameters “strict”
Added Object.setPrototypeOf function
Made Function constructor subclassable
Added Array.prototype.find and findIndex
Added Math.imul
Added ArrayBuffer.isView to check for ArrayBuffer view objects
Added Clause 15.19 defining the content of the build-in iteration module. Coontains built-ins needed to support generators
Disallow Unicode escapes as RegularExpressionFlags
Moved Object.prototype.__proto__ back to Annex B. It’s a simple access or that is not Realm specific.
Added in Annex B __proto__ property keys in object literals
Added placeholder in Annex B for defining syntax of html-like comments
In Annex B, first cut at block-level function declaration legacy semantics
Added RegExp.prototype.compile to Annexs B
Fixed handling of negative integer indices for typed arrays. Elimiante ToPositiveInteger abstract operation
Typed Arrays are allowed to stre values using native endianess.
Fixed various bugs in class declaration semantics
Dates never expose -0 as a time value
Resolved Bugs: 1469, 1461-1460, 1458, 1452-1451, 1449, 1446, 1442-1435, 1433, 1432-1414, 1411-1407, 1404, 1403-1401, 1399-1397, 1395-1392, 1389-1376, 1374-1366, 1363-1361, 1359, 1357-1355, 1352-1348, 1346, 1344-1342, 1340-1338, 1336-1318, 1316, 1314-1301, 1299-1296, 1294-1291, 1289-1288, 1286-1285, 1284, 1282, 1280-1277, 1272, 1253, 1117
Allen