Description of problem:
Anaconda smartly installs a group platform-<autodetected_by_systemd>, which is often great and convenient but sometimes not wanted. For example, when installing a virtual machine to be later used as a container image, this is very damaging. Even explicitly listing the packages not to be installed like:
"""
%packages --excludedocs --instLangs=en --nocore --nobase 
-@platform-kvm
-qemu-guest-agent
"""
does not help. Packages are still installed against users explicit commands.

To spell it in the most general way, it would be nice to have a mechanism to defend against installing any package not explicitly requested.

Version-Release number of selected component (if applicable):
anaconda-21.48.22.121-1.el7

How reproducible:
deterministic

Steps to Reproduce:
1. kickstart with the snippet above
2. repo with a group "platform-kvm" containing "qemu-guest-agent" package
2. install in a kvm-based virtual machine

Actual results:
qemu-guest-agent installed

Expected results:
qemu-guest-agent not installed

Additional info:
platform-kvm group appeared with rhel 7.4