If we're being overly pedantic, the Visual Studio Code that you download from https://code.visualstudio.com/ isn't actually open source. It's analogous to Google Chrome with the source on GitHub analogous to Chromium.

Explanation from Microsoft employee: https://github.com/Microsoft/vscode/issues/60#issuecomment-1...

Visual Studio Code license: https://code.visualstudio.com/license

Official vscode faq - licensing section https://code.visualstudio.com/docs/supporting/faq#_location