The Separation of Concerns (SoC) is a fundamental design principle in ASP.NET Core MVC. It advocates for dividing the application into distinct and separate components, where the Model handles data, the View manages the presentation, and the Controller orchestrates the flow of data between them. This separation enhances maintainability, testability, and scalability.

Razor Layout Views in ASP.NET Core are primarily used to define the common structure or layout that multiple Razor views within your application will share. This allows you to maintain a consistent look and feel across various parts of your web application. They help separate the presentation logic from the content-specific views.

To create a new ASP.NET Core MVC project, you would typically use an integrated development environment (IDE) like 'Visual Studio Code.' Visual Studio Code provides excellent support for ASP.NET Core development, including project templates and extensions that streamline the development process.

The project.json file was used in the early versions of ASP.NET Core (then known as ASP.NET 5), but it was replaced with the .csproj file format in .NET Core 2.0 and beyond. The project.json file defined project dependencies and configuration settings.

Custom middlewares in ASP.NET Core are created using a delegate with the signature Func. This delegate takes an HttpContext as input and returns a Task, allowing you to write custom logic to handle requests and responses in the pipeline.

To specify multiple roles using the [Authorize] attribute, you can separate them with commas inside the Roles parameter, like this: [Authorize(Roles = "Admin, Manager")]. This allows access to the action or controller for users who belong to either the "Admin" role or the "Manager" role or both.

The "Build Scripts" would NOT typically be found in the project.json file. Project.json primarily focused on project structure, dependencies, and target frameworks, whereas build scripts were typically defined in other build-related files or tools specific to the build system.

Continuous Deployment (CD) is a deployment strategy where code changes are automatically deployed to production after passing automated tests. It enables rapid and reliable software delivery, ensuring that new features and bug fixes are quickly available to users.

The commonly used command to create a new migration for ASP.NET Core Identity changes is 'dotnet ef migrations add'. This command generates a new migration file containing the necessary SQL scripts to update the database schema based on changes in your Identity-related code.

In SignalR, a "Hub" is used to describe a group of connections that can be broadcast to. Hubs provide a high-level API for organizing connections and managing communication between clients and the server in real-time applications.