This feature policy allows developers to selectively disable certain CSS animations through the Feature-Policy HTTP header or the <iframe> "allow" attribute. Slow and inefficient CSS animations add delays to layout and paint intervals. This policy lets developers restrict layout-related animations on their own web page or on certain third-party origins in embedded contents.
Docs: https://github.com/WICG/feature-policy/blob/master/policies/animations.md
Samples: https://feature-policy-demos.appspot.com/animations.html?on