Описание тега web-animations
Web Animations defines a model for supporting animation and synchronization on the Web platform. It defines a programming interface to the model that may be implemented by user agents that provide support for scripting.
Official documentation, as published by CSS Working Group and SVG Working Group.
Github: https://github.com/w3c/csswg-drafts
IRC: ircs://irc.w3.org:6667/webanimations