Xcode: URL Types: Icon?

Question

The Xcode docs, explain that the CFBundleURLIconFile key contains the name of the icon image file (minus the extension) to be used for displaying URLs of this type.

My remaining questions are:

1. What icon image should I use? Like, if the URL type is for another app, should I use that app's app icon?
2. What size(s)? If many sizes, how do I name them so that the sizes are used correctly?
3. Where is it displayed? I'm wondering for an iPhone app.

Answer 1

1. Apple does not specify this specifically, but my interpretation is that it should be an Icon representing the application which should/will open/handle URLs of this type.
2. On OS X, the normal approach would be to use an Icon File (.icns). I suspect you should try that on your iOS app. If that doesn't work, duplicate the naming scheme of the the standard app icon files.
3. Try viewing a PDF in Safari on iOS. If you have iBooks, it should show a button saying "Open in iBooks" and shows an icon next to it. This icon is the icon you would be setting.

I hope this is thorough enough to answer your questions. If not, please explain what needs clarification.