Here's a bit of open source news we missed from the end of last year. Volo Airsport, which entered Early Access back in 2014 has been discontinued by the developer and it went open source.
This is something I wished happened more often, ensuring all the time and effort isn't for nothing when a developer plans to move on from a game (especially when not finished). It turns out they actually walked away from it back in 2017, and then suddenly in December 2020 announced it was open source.
The code is now up on GitHub under the GPL3 license. Something to note is that it uses the Unity game engine, so while the project itself is open source it does still rely on the proprietary game engine. A couple of commercial assets they used were also removed for the open source release which are noted on the project page.