Where to find *-app.xml?

Hello, According to this link [http://www.aymericlamboley.fr/blog/air-and-ios-app-options-cutsom-url-scheme-hidden/][1] I need to modify the *-app.xml file in my unity IOS project. But where is this file? Is it the machine.config? If it's the machine.config, I just add what I want to add anywhere within the file? [1]: http://www.aymericlamboley.fr/blog/air-and-ios-app-options-cutsom-url-scheme-hidden/