...The Katana Project (katanaproject.codeplex.com) was Microsoft’s initial effort to implement support for OWIN, and many of the ideas and concepts in ASP.NET 5 were derived from it. Katana had a similar model for building up a middleware pipeline and for hosting on multiple servers. However, unlike Katana, which exposed the low-level OWIN abstractions directly to the developer, ASP.NET 5 instead bridges from OWIN to more convenient and user-friendly abstractions. With a little extra code you can still use Katana middleware in ASP.NET 5 using the OWIN bridge"
aspnet/KestrelHttpServer · GitHub
"a web server for ASP.NET 5 based on libuv.
This project is part of ASP.NET 5"