URL : https://developer.chrome.com/multidevice/android/customtabs
Behavior in Firefox 55

What steps will reproduce the problem?
(1) In section "Add your app as the referrer" of document
(2) Code example shows to build a URL with Uri.parse(Intent.URI_ANDROID_APP_SCHEME + "//" + context.getPackageName())

Outcome: Intent.URI_ANDROID_APP_SCHEME is an Int flag which resolves to value "2" and the example would build a URI like "2://com.example.app"

Expected: String constant is provided to build URI correctly, like: Uri.parse("android-app://" + context.getPacakgeName())