You are looking at the repository for Vue 2. The repo for Vue 3 is vuejs/core.

Vue.js is an MIT-licensed open source project with its ongoing development made possible entirely by the support of these awesome backers. If you'd like to join them, please consider sponsor Vue's development.

Vue (pronounced /vjuː/, like view) is a progressive framework for building user interfaces. It is designed from the ground up to be incrementally adoptable, and can easily scale between a library and a framework depending on different use cases. It consists of an approachable core library that focuses on the view layer only, and an ecosystem of supporting libraries that helps you tackle complexity in large Single-Page Applications.