<rdar://problem/27825875> For example, CFGetTypeID(webView.title) is not equal to CFStringGetTypeID(), but should be.
I picked a bad example with webView.title, but this happens for APIs that do expose internal wrappers.
Created attachment 285973 [details] Implement -[WKObject _cfTypeID]
Fixed in <https://trac.webkit.org/r204432>.