What exactly do you think they wouldn't want to make public?

That's exactly the kind of fear mongering that I'm talking about. I recommend actually reading up on things.

Here's how it works. When you build from the vscode repository, you can configure the resulting tool by customizing the product.json file. This file controls things like the Gallery endpoints, “Send-a-Smile” endpoints, telemetry endpoints, logos, names, and more.

When we build Visual Studio Code, we do exactly this. We clone the vscode repository, we lay down a customized product.json that has Microsoft specific functionality (telemetry, gallery, logo, etc.), and then produce a build that we release under our license.