Some extra background: I worked on a predecessor of this with Matthias about two years back. We had to build a web video player with a lot of advanced capabilities, and found that no open source or commercial player framework would give us what we needed as developers to deliver something really good. I've since moved abroad and haven't been involved with this directly.

A lot of the ideas we came up with made it into this project, and what Matthias did differently in this iteration (like adding Typescript and improving how you write extensions) look really good. You can consider this to be an alternative to video.js, for example, but with easier ways to build advanced extensions without having to fall back to pretty oldschool ways of doing JS.

Matthias' default UI for example is built in React, but there's nothing stopping you from not using his UI extension and building your own that works however you want. Because of the heavy use of Webpack bundle splitting, if you don't use the built-in UI React won't even be loaded, and that approach is core to how this is designed.