The recently added MVVM implementation (in JavaScript) is excellent, but could benefit from some clarifying in-code comments. Please read through the code and provide comments explaining key features where you can.
This is a big task and can be adopted by multiple people. It is not necessary that any one assignee does all the work: Each person involved can do small parts, and hopefully we'll achieve fulsome documentation. Feel free to contribute only as much as you understand or know!