dotnet_runtime/docs/project/copyright.md

Copyright

.NET is a member project of the .NET Foundation.

Source copyright is held by ".NET Foundation and Contributors", while binary distributions (and associated copyright) are provided by a variety of parties.

Source License

The .NET project primarily uses the MIT License for code and Creative Commons licenses for non-code assets, like documentation, swag, and brand content.

We use the following approach for code contributions:

• New code is licensed as MIT, per repo license and via file headers.
• Contributions (like ports) can be based on existing code or algorithms that are licensed with a permissive OSI-approved licenses (for example, MIT, Apache 2, and BSD) and should be ackowledged in the repo THIRD-PARTY-NOTICE file.
• Non-product contributions (like tests) can be based on existing code or algorithms that are licensed with any OSI-approved license (including GPL) and should be acknowleged in a local THIRD-PARTY-NOTICE file (for example, SciMark/THIRD-PARTY-NOTICES).
• We will typically reject the use of product code licensed with Creative Commons or public domain licenses given their lack of universal acceptance.
• The .NET Foundation Contribution License Agreement (CLA) is used to license contributions from contributors.

More mechanical guidance is provided in CONTRIBUTING.md.

References:

• https://opensource.org/faq#cc-zero
• https://opensource.org/faq#public-domain
• https://opensource.stackexchange.com/questions/1717/why-is-cc-by-sa-discouraged-for-code
• https://gitlab.com/fedora/legal/fedora-license-data/-/issues/104
• 11a7b58ea6/data/CC0-1.0.toml (L11)

Binary License

Microsoft distributes binary builds of .NET per the following description. Distributions from other parties may differ.

• Binary archives, installers, packages, and containers are licensed as MIT (same as the .NET source license).
• Windows-based distributions include closed-source assets, per License information for .NET on Windows

Patents

Microsoft has issued a Patent Promise for .NET Libraries and Runtime Components.