Now that we have the HTML document.all object defined, including its typeof document.all = "undefined" behavior, do we still need to permit non-standard, non-callable exotic objects to have implementation-defined typeof, as defined in https://tc39.github.io/ecma262/#sec-typeof-operator-runtime-semantics-evaluation ? I'm not aware of any use cases for this in the Web; do other embedding environments need it?

See related discussion at whatwg/webidl#512 @annevk @TimothyGu