[ebertucc]

I'm just going to copy pattpass' response to a similar comment here, because the decision to use Chromium makes more sense with this context:

What benefit does Microsoft have by using Mozilla instead? Earnest question.

Electron, the software framework VSCode uses, runs on Chromium. Github maintained and developed the framework and they are currently owned by Microsoft. If Microsoft contributes to Chromium and improves performance they benefit in a lot of places: their new browser is improved(Edge Chromium), their own framework(Electron), and their own product (VSCode).