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 licensed as 3-clause BSD, which allow developers to make closed source proprietary product on top of open-source code. Microsoft Edge isn’t opensource as Google Chrome isn’t open-source while they’re both built on chromium.
I don’t think Microsoft ever claimed it was open-source.
https://archive.is/sdmDL