Nine months after Project IDX was first unveiled, Google's web-based development environment is now available to the public as an open beta. This marks the end of the waiting list for Project IDX, which enables cross-platform development for the web, Android and iOS directly in the browser.https://www.notebookcheck.net/Browser-based-IDE-Google-s-Project-IDX-now-available-in-public-beta.838853.0.html
It's just a Visual Studio Code skin. The same could be done with the stock VS Code + Extensions.