OpenID Connect and OAuth 2.0 Framework for ASP.NET Core
...It is part of the .NET Foundation and operates under their code of conduct. It is licensed under Apache 2 (an OSI-approved license). Active development happens on the main branch. This always contains the latest version. Each (pre-) release is tagged with the corresponding version. The aspnetcore1 and aspnetcore2 branches contain the latest versions of the older ASP.NET Core based versions.