What is esim?
ASP.NET Core 3 is still preview.
When you host your domain as GitHub page, GitHub doesn’t give you option to host your domain email.
GitHub allows your use your own domain name for GitHub page and it’s very easy to do.
Now it’s popular to use static site generators, see for example Scott Hanselman’s article: Exploring Wyam - a .NET Static Site Content Generator:
Okay, now I have blog using GitHub pages.