in Mojave > System Preferences > Security & Privacy > Privacy > Automation an Installer requires access to System Events.
How to find out to which app this belongs and eventually (if wants to sent data to some servers) how to delete it?
Installer is the built-in macOS app for installing packages. The Installer app itself does not belong to any app in particular; it runs any package given, usually by double-clicking a pkg from Finder.
Installer will request Automation permission when a script in a package requests such, which will occur at the time of running the package. When such a request occurred, you would be installing an app on your system, hence it would be this app’s installer scripts which would trigger this.