I think thats how the miui works (Maybe not just miui, probably any higher android version). Since you don't give any main permission until it needs it. For example if it needs storage access it will prompt for it when it needs it.… If it needs extra special permissions like display over other apps you have to manually permit it to do so.
So the package installer in higher android version just skips that. Ok as I am writing it I am feeling more sure that its with higher android version not just miui. Anyway main answer is this as you don't give any main permission that can affect your security by default (unlike older android version where you would give the permission when installing the app) the package installer removed showing permissions that are given to the app(or the permission it may need).