From Xojo Documentation
Called when your app is passed a URL.
|url||The URL resource to open. This could be a network resource or a file.|
|identifier||The bundle identifier of the application that sent the URL request to your application.|
|annotation||When the URL is a file, the annotation is information about the document type.|
|openInPlace||If the URL is a file, openInPlace will be True if you can open the file directly. if it's False, you must copy the file before attempting to open it.|
To add a URL scheme to your app, click on iOS under Build Settings in the Navigator then click on the Advanced tab in the Inspector. Enable Custom URL Schemes then click the Options button to add one. The scheme is the portion of the URL before the colon. For example, to add a scheme called feedback using with createcase as the path, enter feedback://createcase.