Change record status: 
Project: 
Introduced in branch: 
8.x
Description: 

The normalize library (core/normalize) was being added by the system module. Therefore, the CSS was added for every theme. It is now only included by Classy. If your theme is not using Classy, you can include the normalize library in your theme's .info.yml file.

libraries:
  - core/normalize
Impacts: 
Themers