Right now there is no InAppBrowser error event.
That's useful for several reasons and in my case I need it for OAuth. The redirect URL is non-http so I get this error: webView:didFailLoadWithError - The URL can’t be shown
If I would have an error event containing the failing URL in the payload I could actually parse out the refresh/access token etc. from the OAuth flow.
Besides the error event is also useful in general to get a hook for when a URL is not working.