Not only do we not always capture stack info (bug 686587); after an exception is thrown we discard most of the information before reporting it. The console only gets the error message, url, and line number. See also bug 683733. We should keep a stack and the exception value at least.
One more thing to add to this that in case of throwing a simple string,like throw 'myError' even the line number and the url are not stored.
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