What purpose does badge_count_class_name have? Documentation?

Question

I have this code below to set a badge count on my application icon. The code has copied from Stack Overflow. The intent uses a parameter badge_count_class_name. Given the package name is already passed as a parameter the system could already find out the launcher class name, right? So what purpose does the badge_count_class_name actually have?

Also I am unable to find any documentation on the intent and the supported parameters. Anybody an idea on how to find documentation on the android.intent.action.BADGE_COUNT_UPDATE intent and its parameters?

    Intent intent = new Intent("android.intent.action.BADGE_COUNT_UPDATE");
    intent.putExtra("badge_count", count);
    intent.putExtra("badge_count_package_name", getPackageName());
    intent.putExtra("badge_count_class_name", launcherClassName);
    sendBroadcast(intent);