If you search for “Microsoft edge open source” there will come out a lot of blog posts from five years ago praising a Microsoft Press release that announces that edge is open source .
But then, there’s no actual repository, the GitHub is empty, there’s only the MIT license and that’s it
So, they publish the source somewhere or it’s just marketing?
Chromium is open source and thats what Edge (and Chrome) is built on. So yeah you cant really say that Edge is directly open source I guess.