There are only two hard things in Computer Science: cache invalidation and naming things. -- Phil Karlton Learn how to add cache headers for static files and file action results.
What formatters do is format your response and request in your preferred data formats. For example, JSON formatters; if used, would format your request and response body in JSON. Learn how to build a custom Yaml formatted in .NET
There are a bunch of "dotnet" templates readily available for use. That's all fine and dandy! But what about creating your templates? Learn how easy it is to ship your runnable projects as templates for your team.
If you are adding API versioning to your existing API project, you can tell ASP.NET Core to treat the undercoated controllers and actions to have version 1.0 by default. To do that, configure the AddApiVersioning() service with AssumeDefaultVersionNumberUnspecified flag.