It is technically separated out. Just shipped with .NET Core in a big framework bundle called ASP.NET Core (which is in all containers etc anyway). Look at the

It is technically separated out. Just shipped with .NET Core in a big framework bundle called ASP.NET Core (which is in all containers etc anyway). Look at the techempower benchmarks implementation .. they run as close as possible to Kestrel. They have variants with raw kestrel interface, some with low-level middleware (I guess with express like routing) and then full-blown MVC like comfort.