Visual Code is a brand new tool, and we only use the telemetry to help improve product quality, and better understand how our tool and features are being used so we can know how to improve VSCode. By the time we exit Preview, we will provide a way to opt out of this reporting.
The Visual Studio Code shell is built on GitHub's Electron Shell, but the editor is a new and improved version of our own Monaco editor, which we use on Azure Websites, Visual Studio Online, and a number of other web sites, and in the F12 Tools in Internet Explorer.
Visual Studio Code is already built on top of a number of open source projects we've created or are contributing to, including the Roslyn compiler and language tools, OmniSharp, Typescript, and GitHub Electron. We are still in an early stage and we're evolving our architecture - and we'll look at what we open source, and how we do it, as part of that.