Are URI scheme requirements/standards unique to each platform?
I'm wondering if the standard/requirement ends after the colon/double forward slash "://" of the URI?
I will use the Facebook mobile app as an example. It is a multiplatform mobile app. If you wanted to create a QR Code that links people to your page, you have to have two different QR Codes to work for iOS and Android platforms.
The iOS platform URI scheme is "fb://profile/" to open a page in the Facebook iOS app. However, the Android URI scheme is "fb://page/" to open the same page using the Facebook Android app.
Do platforms dictate the URI scheme past the colon/double slash? Is it a requirement/standard?