"Internet plug-ins:" setting missing under Preferences > Security > in Safari
Hello everyone,
Decided to post this Issue since it took me a while to figure it out myself and I'm guessing that someone else might be experiencing this as well. As you can see the option "Preferences > Security > Internet plug-ins:" is missing. The solution for this issue is to select the "Websites" tab instead and there you will find a "Plug-ins" section which allows you to enable and disable plugins generally or for single websites.
I was originally using MacOS X Snow Leopard and upgraded to El Capitan. It thought that upgrading to High Sierra might resolve this anomaly and proceeded with the upgrade but to no avail. Maybe someone could explain what this discrepancy in Safari's security settings is due to.
I hope this was useful to some of you.
macOS High Sierra (10.13.1), Internet plug-ins in Safari