Sure- but that was conceived from the beginning as an open-source project, and isn't even truly "compiled"; it's designed to be hackable. Calc.exe is a core Windows utility, and was open-sourced after the fact.
Chakra was a many years old code base that was open sourced a few years ago, and we got a large number of pull requests from the community merged and shipped with windows and in chakracore releases. Object.fromEntries is one that immediately comes to mind but I know there were more. It happens across a lot of our projects!
Yeah, with the current CEO Microsoft got really active in the OSS Community. Still MS with Telemetry, like in the pre-compiled VSCode, but it's the right direction!