3D hand model: "Rigged Hand" by J-Toastie
Source: https://poly.pizza/m/BEy8jbxm6A
License: Creative Commons Attribution 3.0 (CC-BY 3.0)

This model is used (tinted, scaled, mirrored for the left hand, and posed at
runtime) in the 3D piano hands overlay. Attribution must be retained and shown
to users where third-party credits are displayed.

three.js (build/three.min.js) and GLTFLoader.js are MIT-licensed (three.js authors).
