Role-Based Authorization is a key feature of ASP.NET Core Identity that allows you to manage user roles and claims. It enables fine-grained access control by associating users with specific roles and defining role-based policies for authorization.

To specify the SDK version for a .NET project, you should add a "global.json" file to the project's root directory. This JSON file allows you to define the desired SDK version, ensuring consistency among team members and across development environments.

Razor views in ASP.NET Core commonly use the file extension ".cshtml." This extension indicates that the file contains both HTML markup and C# or VB.NET code, which can be executed on the server to generate dynamic web content.

The Output property of a custom tag helper is of type TagHelperContent. It allows you to manipulate the final HTML output produced by the tag helper, giving you fine-grained control over the generated markup. You can append, prepend, or replace content within the HTML element.

To conditionally branch the middleware pipeline, you can use the UseWhen method provided by ASP.NET Core. This method allows you to specify a condition, and based on that condition, you can choose whether to execute certain middleware components or not. It's a powerful way to customize the pipeline based on specific criteria.

To apply a custom authorization policy using the [Authorize] attribute, you should use the syntax [Authorize(Policy = "CustomPolicy")]. This tells ASP.NET Core to use the "CustomPolicy" when authorizing access to the action or controller.

You should define a namespace that you want to use across multiple Razor views in the _ViewImports.cshtml file. This file is specifically designed to consolidate 'using' directives, making them accessible throughout the views that share it, thereby improving code organization and reusability.

In ASP.NET Core Razor views, Master Pages have been replaced with "Layout Pages." Layout Pages define the overall structure and common elements for views, similar to Master Pages in previous versions of ASP.NET. They provide a consistent layout for multiple views within your application.

In the MVC pattern, the Model is primarily concerned with how the application's data is represented and manipulated. It encapsulates the business logic, data storage, and interactions with the database. It acts as a bridge between the Controller and the View, providing the necessary data to be displayed.

Running tests after developing a new feature to ensure that existing functionality remains unaffected is known as Regression Testing. It helps catch unintended side effects or bugs introduced by new code changes.