Microsoft announced today that they're preserving a bit of history here - with Zork I, Zork II, and Zork III now officially and clearly open source. The source has been around for a while but now it's all proper.
From the announcement they said:
Today, we’re preserving a cornerstone of gaming history that is near and dear to our hearts. Together, Microsoft’s Open Source Programs Office (OSPO), Team Xbox, and Activision are making Zork I, Zork II, and Zork III available under the MIT License. Our goal is simple: to place historically important code in the hands of students, teachers, and developers so they can study it, learn from it, and, perhaps most importantly, play it.
They didn't put up their own repositories though, instead they decided to collaborate with Jason Scott of the Internet Archive, to officially send in pull requests to add the MIT license to each of the existing repositories. That's quite a nice way to do it. Those existing classic source repositories are now considered the canonical home for the Zork source code.
Microsoft said they chose the MIT license for its "simplicity and openness because it makes the code easy to study, teach, and build upon".
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