Unity publishes editor and engine source code without making it open source

Unity has put the source code of its engine and editor online for reference purposes. This means that the code can only be viewed and that it is not an open source project. Pull requests are also not honored.

Unity developer Aras Pranckevičius writes in a blog post that the C# code has been put online because it has been done before by some people in the community. They did this by disassembling the code. He writes that the Unity team had “mixed feelings” about this practice, although its terms explicitly allow it so that people can better understand their own projects. However, disassembling would also have drawbacks in that it is clumsy and does not provide insight into comments and variable names. That’s why the team decided to self-publish the code on GitHub.

It does this under a so-called reference-only license, which states that viewing the code is intended to better understand or improve the performance of your own games. Modifications to the code are not allowed, which means that pull requests are also not honored. Moreover, the team says it does not have the legal or organizational capacity to do so. It also claims to have ‘nothing against open source’. For example, it says that it wants to publish its source code in this way if there is still money to be made that way, but that this is not the case. The engine code will therefore remain Unity’s property for the foreseeable future.

Unity is a cross-platform game engine that supports 2d and 3d graphics. Several games make use of the engine, such as the recent Subnautica.