In an MVC (Model-View-Controller) project, you would typically place business logic or data access logic in Model classes. Models represent the data and business logic of your application, keeping the controller actions focused on handling HTTP requests and the views focused on rendering data. This separation of concerns is a key principle in MVC architecture.

To better organize and prioritize routes in a large-scale application with attribute routing, you can use Route Prefixes. By prefixing routes with common segments, you can group related routes together and reduce the risk of overlapping or conflicting routes. This strategy helps maintain a clear and structured routing system.

In ASP.NET Core, the default layout for Razor views is typically specified in a file named "_Layout.cshtml." This file contains the common HTML structure, including headers, footers, and navigation menus, that will be applied to multiple views in your application.

ASP.NET Core achieves cross-platform compatibility by embracing .NET 5 and later versions. These versions are designed to be cross-platform, allowing ASP.NET Core applications to run on Windows, Linux, and macOS. Unlike the older .NET Framework, which was primarily Windows-centric, ASP.NET Core's use of .NET 5 and later versions enables platform-agnostic development.

The RefreshSignInAsync method can be used to refresh the sign-in information of a user in scenarios like role updates or other security-sensitive operations. This method generates a new security token for the user, helping to prevent token-based attacks and ensuring the user's session remains secure.

To ensure that Entity Framework Core doesn't throw detailed database errors to the client, you should use "Exception Handling Middleware." This middleware intercepts exceptions, handles them, and returns a user-friendly error response to the client without exposing sensitive database details.

JWT or JSON Web Tokens are often used in conjunction with the Bearer authentication scheme in ASP.NET Core. The Bearer scheme is commonly used to secure APIs and web applications, where a client includes a JWT token in the HTTP Authorization header to authenticate and authorize their requests. This scheme is based on the bearer token concept, where possession of the token is sufficient for authentication.

In advanced routing scenarios where the built-in routing capabilities of ASP.NET Core are insufficient, developers can leverage the RouteBuilder class. It provides more fine-grained control over route configuration, enabling customization and complex routing setups.

To optimize EF Core queries, you can use a SQL Profiler tool, such as SQL Server Profiler. These tools allow you to capture and review the generated SQL statements, analyze query performance, and identify areas for improvement. It's a crucial step in fine-tuning your application's database interactions.

Routing in ASP.NET Core MVC is primarily responsible for handling incoming HTTP requests and mapping them to the appropriate controller actions. It determines which controller and action method should respond to a particular URL, making it a crucial part of request handling and processing.