Web animations covers the techniques for adding motion to web interfaces — CSS transitions and animations, the Web Animations API, and the libraries (GSAP, Motion / Framer Motion, anime.js, Lottie for designer-authored animations) that make complex motion practical to ship.
The discipline has matured beyond "make things move". The current concerns are accessibility (prefers-reduced-motion), performance (which properties trigger layout vs composite-only), and the design taste required to use motion as a communication tool rather than a decoration. Apple and Linear's product motion design are usually the references that come up in courses.