pxt-core-own/webapp/public/monacoworker.js

Microsoft MakeCode, also known as Programming Experience Toolkit (PXT), provides Blocks / JavaScript tools and editors

// see https://github.com/Microsoft/monaco-editor
self.MonacoEnvironment = { 
    baseUrl: "/cdn/" 
};
importScripts("/blb/vs/base/worker/workerMain.js");