I noticed that BABYLON.DeviceSourceManager is not included in babylon.max.js but it’s included in the playground. Where do I get it?
Are you sure you are using the preview version ? You can see it in here: https://raw.githubusercontent.com/BabylonJS/Babylon.js/master/dist/preview%20release/babylon.max.js
Which is available at https://preview.babylonjs.com/babylon.max.js
not experimental as our preview version are usually quite stable