Kestrel is the lightweight, cross-platform web server that is used by default with ASP.NET Core. It's designed for high performance and is well-suited for hosting ASP.NET Core applications. Developers can also use it in combination with reverse proxy servers like Nginx or Apache for production deployments.

ASP.NET Core Identity provides user authentication, but it doesn't include OAuth as a standard provider. OAuth is a separate authorization framework that can be used with ASP.NET Core for scenarios like external logins, but it's not part of the Identity system.

In the ASP.NET Core middleware pipeline, the order in which middleware components are added matters. If the middleware order is incorrect, it can lead to unexpected behavior. Middleware components are executed in the order they are added to the pipeline.

Identity is an ASP.NET Core feature that allows you to implement authentication and authorization logic to secure your Web APIs. It provides user management, role-based access control, and authentication mechanisms like JWT (JSON Web Tokens) out of the box. Developers can easily integrate Identity into their ASP.NET Core applications to manage user authentication and authorization requirements.

To achieve different headers for specific pages in an ASP.NET Core application, you can create a custom layout for those pages. This approach allows you to maintain a consistent structure while customizing headers for specific pages.

In ASP.NET Core MVC, the business rules and logic are typically located in the Model. The Model represents the application's core logic and data handling, making it the ideal place to implement and enforce business rules. This separation of concerns helps maintain a clean and organized codebase.

The best way to customize the password hashing algorithm in ASP.NET Core Identity is by implementing a custom PasswordHasher. This allows you to have full control over the hashing process, ensuring it meets your specific security requirements.

In ASP.NET Core unit testing, the [Test] attribute is commonly used to signify a method as a test method. This attribute is part of popular unit testing frameworks like MSTest and xUnit.

The ActionResult action result provides the flexibility to return different types of responses based on conditions. It's a base class for other action results in ASP.NET Core, allowing you to return various derived result types like JsonResult, ViewResult, or ContentResult. Depending on your conditions, you can choose the appropriate derived result type to return different responses, such as JSON or HTML.

EF Core provides a feature called "Raw SQL Queries" that allows developers to execute raw SQL commands directly against the database. This feature is useful when you need to run complex or specific SQL queries that cannot be easily expressed using LINQ or the query builder methods provided by EF Core.