Prevent application to make silently install file(s) or making changes 'Request Install Packages' let's say if an app has this permission ex- facebook(Check it in playstore head to facebook then 'app permissions' and click 'see more'. I used to read articles related to security threads to the device and while reading what this permission can bring to the device is look suspicious as it can trigger to install/make change to an existing app silently(without taking any permission from user). 


  I have then checked many apps that i was going to install but this setting makes me think that it may include security issues. Isn't it ?


Is there any way to prevent making changes silently ?
Can an antivirus prevent these changes to the device's app ?

Android Version: Nougat 7.0
Request install will require the user to accept the install, this permission is probably used for two things on Facebook specifically   


Redirecting users to install Messenger   
Redirecting users to install Updates to Facebook   


I understand your concern with allowing an application to install other applications without notification, but this is not possible, the permission only allows the application to redirect the user for installs, you still need to accept the installation.

You can prevent the application by using a permission manager, some of them recompile the application and completely disable the permissions, other use AppOpps to disable the permission.